In the early hours of Sunday 11 January 2009, after a sleepless and painful night, I am admitted to my local NHS hospital with suspected appendicitis. It had come without warning and very soon things began to go wrong.

Day 2, 9am A young consultant anaesthetist arrives, squats beside my bed and shakes my hand. "I'll be looking after you," he tells me. "I've talked to the surgical team and I agree an operation is necessary... Just one thing. The last thing you might feel before we put you out is my hands round your throat. You might feel as if you are being strangled."

"...OK."

"This is to prevent the contents of your stomach rising up into your mouth. But don't worry."

Afterwards, a consultant tells me it wasn't appendicitis but diverticulitis. Diverticula are small sacs that protrude from weak points in the colon like bulges in a bicycle tyre. Occasionally they become infected and rupture. "There was some infected colon, so we took out a section and stapled you back together," the consultant says. "Slightly more complicated than we anticipated, but you should be fine. Any questions?"

"Can I have something for the pain?"

Night 2 I am put on a high-intensity ward I later learn is fondly called "Beirut". There are three nurses to six patients. This is where the seriously ill and the immediate post-op patients reside.

Beirut is one of eight digestive diseases wards. Perhaps a third of the residents are here because of liver problems caused by alcohol abuse. I've been watching the debate on TV about increasing the cost of alcohol as a way of combating alcoholism, and the £3bn the NHS spends a year treating drink-related illnesses. Most of the alcoholics I encounter in hospital are happy to admit they spend £500-£800 a month on booze. These are not well-heeled, white-collar drinkers. Many subsidise their drinking by benefits and thieving. Food is low on their list of priorities.

Each ward holds six beds, three against each wall. I am in the middle bed on the right-hand side. In the bed closest to the door on the other side is a man I will call Alcoholic Alan. His skin is yellow and his eyes are closed. Next to him, and directly facing me, is a dying man. The curtains around his bay are closed and throughout the night distraught relatives arrive to bid him farewell.

To my right is a cadaverous man, also in his 60s, who keeps taking off his gown and displaying his genitals to the nurses. Long-term abuse of alcohol has rendered him infantile. He rarely sleeps and spends all night calling out, "John Terry, John Terry, John Terry."

The curtain on the bay to my left is half-closed, so I can't see my neighbour - another liver patient. I can, however, see his white shins and purple feet. A surgeon and nurse occasionally attend to him, using what looks like an electric razor on the skin. The smell is appalling.

At a little after 4am, the man opposite dies. I hear the sudden outpouring of grief. More relatives arrive. The ward is flooded with the smell of conflicting perfumes. The body is removed two hours later to the accompanying chant of "John Terry, John Terry, John Terry".

Day 3 A nurse arrives with a large syringe of morphine. The drug is connected directly to the cannula in my arm. To trigger the syringe, I press a green switch. Every hour a nurse arrives to check my "pain score" on a scale of one to 10. For most of the day I award it eight or nine, reserving full marks for some unimaginable future horror.

Night 3 It's 3am and Beirut is busy. It's a male-only ward, but because of space shortage a woman has just been wheeled in after an operation. The smell of shit fills the room. Several nurses attend to her. She moans and screams in pain.

I can't sleep anyway - the hallucinations are getting worse. I have not slept for three nights. I feel sick. My temperature is high and the morphine no longer seems to take the edge off the pain in my stomach. I reach for my wound. It feels wet. I touch my fingers to my nose and smell bile.

To get away from the chaos in the ward, I take my fluid stand to the lavatory and tentatively raise my pyjama jacket. Green bile is pouring down my stomach from the stapled wound. It smells rank. I vomit and pull the alarm cord. A nurse arrives, gently tells me not to worry and instructs me to return to bed. I vomit again. The doctor arrives, instructs the nurse to send me for an x-ray and tells her to tube me.

"This will not be nice," she warns, "but you must work with me and it will be easier. OK, darling?"

"OK."

I feel a sharp tube entering my nose. I swallow and feel the tube in my throat. I retch. Over the following four days, the contents of my ailing stomach drain into this bag. My bowel, meanwhile, is taking a well-earned rest.

I learn the next day that the crisis was caused by an enterocutaneous fistula - an open channel between a tear in the colon at the site of the operation and the surface wound. Nearly 800ml drains from the wound on the first day. The hope is that the fistula will slowly heal itself. If it doesn't, another operation will be necessary.

Day 5 Barrel Man arrives on the ward early in the evening. His legs are white and spindly, but his belly is the size and shape of a beer barrel. His belly button extends four or five inches from his stomach and is the width of a baby's arm. He was brought in because Meals On Wheels had alerted the police that his door had remained unanswered for two days. The police broke in and immediately called an ambulance. This elderly man is a former alcoholic, his liver is not functioning and his stomach now has many litres of liquid in it.

Barrel Man is immediately put on a drain. Several clear bags of fluid are emptied from his stomach every couple of hours. During the night, at around 2am, we are awoken by the sound of a cry and a splash of liquid. The room fills with the aroma of faeces. A nurse dashes in, switches on the light and pulls Barrel Man's curtain round, but not before we have glimpsed the pool of blood and faeces on the floor. Two doctors arrive. Barrel Man is wheeled down to the theatre. We don't expect to see him on the ward again. With typical understatement, the following day the nurse reports his condition as "very poorly".

Day 6 The wound is like a tiny, evil mouth in my stomach. Occasionally it belches and fluid plops out and into the stoma bag, causing a burning sensation as the acid hits the skin.

Day 7 Because I have not eaten for a week and my weight has dropped by three-quarters of a stone, the nutritionist tells me I'm to be fed intravenously. I watch a white tube being fed into my vein until only an inch or so is visible just above my inner elbow joint. I can now be attached to a bag that will provide me with much-needed nourishment.

Day ? I have lost all track of time. Days blur into nights. I'm convinced I have been here before and had a similar operation two years ago. My wife assures me this is not the case. I can't sleep because each time I close my eyes I fall into the same hellish dream. I am walking along a corridor and I stumble. I roll over, head over heels, faster and faster, hitting every jagged surface I pass. The agony is immense. Finally I hit a wall. I am lying on my back. I know I have just experienced my death. I have not slept for three or four nights, but at last I have found a solution to this mental turmoil. I will walk to the beach and swim out to sea. I will not feel the cold because the morphine will prevent it. The desire for the salt water against my skin is as fierce as a raging thirst. I have no intention of drowning myself, but no plans beyond swimming out to the pier.

The night sister is at the desk with one of the nurses. "Where are you going?" she asks me.

"For some fresh air."

"The nurse will come with you. We'd hate you to fall over. And hurt yourself."

Somehow the sister knows. The nurse comes outside with me. She tells me it's freezing cold, but it seems warm to me. I return to bed and watch Time Team on television until the small hours. I am grateful when dawn breaks.

Day 18 Nearly two feet of snow have fallen during the night. The transport systems of the city are paralysed - there are no buses, taxis or trains.

"It's too cold to snow," Detox Dave says, despite the evidence to the contrary. "I blame global warming." He was admitted because of stomach ulcers. While on the ward, he chose to be detoxed.

My wife arrives to visit me after walking for an hour and a half. She has not missed a day. Without her visits and the support of my son and daughter, this would be intolerable. Many of the liver disease patients are unvisited.

Day 20 Most of the alcoholics on the ward are hardcore drinkers who see a hospital stay as a necessary but inconvenient interruption to their consumption. Counselling is routinely offered. Occasionally it is accepted.

Alcoholic Alan has not yet opened his eyes. His hair has been razored to his skull, so he now looks like a Dickensian criminal on a poorhouse bed. His partner, who is some kind of trained healthcare assistant, takes care of him: she changes the sheets, tries to feed him. She dispenses the care with tender brutality, whispering poisonous comments to him as she attends to him. She is wrecked from lack of sleep and fear. I overhear her talking to a nurse: "He had three chances and he blew it. This is his fourth time in here."

"You're coping with it very well."

"Yeah, but I'll be in a puddle at the end."

Alan purrs like a cat.

The following morning Alan is gone. He died in the night. He was in his mid-30s.

Day 21 This being a digestive diseases ward, bowels and the operation thereof provide an endless source of discussion. The term "a regular guy" takes on a whole new meaning in here. When Barrel Man returned last night, his first request was for a commode. When it was delivered, he was soon calling out to the nurse that he had provided her with "a lot of black stool". The nurse emerged from his curtained cubicle bearing the sample at arm's length. We present our stool samples to the nurses like proud schoolchildren. They are always received with thanks.

Flatulence is considered a sign of improving health, therefore any fart is unleashed loudly across the ward, usually earning spontaneous congratulations and words of encouragement - which is fine, except, of course, when the practice continues during visiting times.

Day 22 Despite being discharged only 24 hours ago, Detox Dave is back to visit his friend, Baz. He struts around the ward as if it was the scene of his greatest triumph. When he leaves, I ask Baz how Dave is doing and Baz says he'd had a couple of cans of strong lager that afternoon, thus rendering his detox on the ward fruitless. He'll undoubtedly be back within a couple of months.

Meanwhile a new alcoholic has been delivered to Beirut ward. His screams can be heard from some distance away. Nurses emerge white-faced from his cubicle. He continues screaming for a few hours, but falls silent around midnight.

Day 23 Barrel Man tells me that, until recently, he lived with his mother. Although he has not drunk anything for almost a year, he is now living with the effects of the 12 years during which he drank a bottle of gin a day. They had hoped his liver would regenerate when he stopped drinking, but it's too badly damaged. It's unlikely he will be offered a transplant because of his age and he has been told he'll probably die within three months. His mother is in a nursing home and he has yet to phone and give her the news. He is never visited.

I watch him now across the aisle. When his eyes are not closed in sleep, he stares out as though he is peering towards the horizon, looking towards his next destination.

Day 24 Startled Nigel came in badly bruised. He is very well spoken, cadaverous, and has chosen to wear a nightshirt. Nightshirts are rarely tied correctly at the back, and those who wear them tend to have their arses on display each time they leave their bed. He has tumours on his bladder and is another former alcoholic. He has just undergone a cystoscopy, in which a tube with a tiny scalpel on the end is inserted into his urethra. Matt (another long-term resident) and I are discussing Pain Poker and Matt awards Startled Nigel the winning hand - the equivalent of four aces.

I've learned a lot about pain since I came in here, and I now know I've been lucky to have avoided it for much of my life. I thought I knew what it was: the sharp, sickly agony of a football to the testicles, nagging toothache, a paper cut, a bad headache. Always manageable, recognisable, easily dealt with. But pain comes in many more colours and intensities. The nurses here have a chart with a series of cartoon facial expressions denoting differing degrees of pain. That way, when the agony is too intense for self-assessment, they can award it a score. On the ward it's easy to recognise which of the inmates is suffering. They are the ones who lie silent but not asleep, breathing shallowly, hands often clasped over the centre of the pain, staring straight down the barrel.

Night 24, 2.15am The ward is silent now. Just the regular breathing of Barrel Man and the tinkle of pumps delivering liquids into veins breaking the silence. Rain is being hurled at the window by a high westerly wind and I can see the traffic lights changing and changing - liquid green and amber and red spilling on to the wet road - while no cars wait.

I am afraid that I will remain in the arena of the unwell for ever. The fear always returns at night. I have been on clear fluids for two days now, to test the fistula, which seems to be healing, but I have had violent diarrhoea several times and I am worried. At 3am I take my concerns to the night sister at the front desk. She's used to my nocturnal wanderings and assures me that I am progressing well and that diarrhoea is perfectly normal. She is busy but, as always, finds time to reassure me.

Day 25 The next morning's ward round is brisk. The consultant is not concerned about the diarrhoea either. "We'll put you on a light diet, OK?"

A male nurse delivers two slices of toast, two pats of butter and a tiny pot of Marmite. I contemplate it for a while, then I spread the butter and Marmite, and pause to allow the smell to permeate my nostrils. Then I bite. I feel the soft abrasion of the toast against my palate, the soft, comforting cloy of the butter coating my tongue. I chew slowly. Another bite. Heaven. I can manage only one slice and I await my bowel's response to the first solids I have presented to it in 26 days.

Three days later I am released.

Day 32 After spending four days at home enjoying those things and people I'd for so long taken for granted, I awake with a stabbing pain in my chest. I expect it to pass. It worsens. I am glad I'd reserved full marks on the pain score, because I could now award it. This was a full 10.

Via A&E, I return to the ninth floor for a series of tests that reveal I now have gallstones and an inflamed gallbladder.

In my new ward, inmates conform to the usual statistical breakdown. Two of the five are liver patients, caused by alcoholism. The man to my left has an angry purple rash on both legs which at the ankles is hard and black - the skin crumbling like coal. He announces regularly that his testicles have swollen up to three times their normal size, he hasn't had a shit in seven days and his stomach is giving him a great deal of pain. Crohn's disease is suspected. He tells me he was drinking 13 bottles of sherry a day, spending £800 a month on booze. When I ask why sherry, he says, "It's a drinker's drink" as if that is all the explanation necessary.

He is a compelling presence, his voice like that of a night-time DJ on an offshore jazz station. He rarely stops talking, but often the conversation is directed towards an imaginary congregation. Recent statements: "You know I love you all very much. I'm very fond of you." "Egypt is dying, Egypt is dead." "I am the Count of Monte Cristo." And my particular favourite from today, delivered when he was at the height of his pain: "Beelzebub has visited and taken me shopping."

Facing the DJ is the other liver patient, Seasick Scott. He is an alcoholic, and his skin and hair are so jaundiced they appear a yellow gold colour. He has a tumour on his hip. He spends much of the day calling for the overburdened nurses to make him cups of tea or asking them to wheel him outside so he can have a "ciggy".

The tiny, Borrower-sized old man across the aisle is in great trouble. He can't swallow. His stomach is blocked. He spends all day and night spitting black bile into a cardboard bowl. The smell of it permeates the ward. His slippers are tiny with Power Rangers' logos on them.

Day 37 Five days later my bag is packed. I am dressed and waiting for one last change of the wound dressing before I return home for the second time. The ward is quiet and a consultant's team are visiting Seasick Scott. His curtains are closed. I can't help overhear the conversation.

"...So, whatever happens, the likelihood of us being able to cure this is fairly small. We'll have to discuss where you're going to live... Scott? Let's get the Macmillan nurses to come and see you and have a chat... Anything else?"

"No. Thank you."

"I'm sorry."

The news of his impending death is the first thing Seasick Scott has thanked anybody for since I first encountered him. A phlebotomist arrives and asks if she can take his blood. He refuses on the grounds that he has been given bad news. The curtains remain closed. A moment later I hear him call: "Nurse! Could I have a cuppa tea, please?" Sadly, there's nobody around to answer.

Five minutes later a different consultant's team arrives to see the Borrower. The curtains are drawn around his bay. The Borrower is told that they now have the results of his tests and it's not good news. Like Seasick Scott, he has cancer and it is inoperable. The Borrower doesn't say anything. The consultant says he is sorry but there is little they can do. He leaves him with some literature. When the curtains are pulled back, the tiny old man looks towards me and smiles. "They gave me a book," he says proudly, holding it up, and for some reason the sight of it breaks my heart.

Out I'm out now, although I have to return when the wound has healed for an operation to remove my gallbladder. I caught sight of the DJ and the Borrower when I went in for an outpatient's visit. The Borrower waved. The DJ's eyes were closed in pain. Seasick Scott's bed is empty.

In the press, the debate over alcohol continues and the chief medical officer is now pushing for a minimum price of 50p per unit. The prime minister is apparently against it, not wanting to penalise the great majority who drink "sensibly". Meanwhile, the news that heavy drinkers receive one in four liver transplants, an increase of 60% in the past decade, has angered some. Is alcoholism self-inflicted? Curable? Who can say?

I doubt Detox Dave, the DJ, Barrel Man and Seasick Scott are aware of the recent arguments. They have come too late for Alcoholic Alan. For the regulars on the digestive diseases floor, alcoholism is a disease of the soul; the arena of the unwell, a way station between this world and another place.

• Chris Paling's most recent novel, Minding, is published by Portobello Books