In 1987 the medical journalist Caroline Richmond, who has died aged 82, was shocked at the barrage of protest in response to an article in the New Scientist saying food additives were mostly harmless. Curious to test what else people might believe was harmful, and a fan of wearing bright colours, she wrote a tongue-in-cheek article for the British Medical Journal, “Fabric dyes: are they in the consumer’s interest?”

It suggested wearing brightly coloured clothes might have a range of effects including increasing cancer risk and masking serious psychiatric disorders by making people too cheerful. The article was supposedly issued by the Dye Related Allergies Bureau (DRAB), a subsidiary of the Food Additives Research Team (FART), which Richmond assumed would alert readers to the joke.

However, the charity Action Against Allergy ran the piece in its newsletter in all seriousness and readers contacted Richmond wanting to share their experiences of bright-clothes allergies.

It worried Richmond and convinced her the UK needed a body to call out health misinformation – like the National Council Against Health Fraud that existed in the US. In 1988 she circulated a proposal, “Why Britain needs a counter-quackery organisation”, to like-minded colleagues, and on 1 November 1988 the inaugural meeting of the Campaign Against Health Fraud took place in the Old Bell pub in Fleet Street, London. Some of the other participants included the cancer specialist Professor Michael Baum, the hypoglycaemia expert Professor Vincent Marks and the broadcaster Nick Ross.

In its early days the organisation – which changed its name to HealthWatch (1990) and then to HealthSense (2022) – campaigned against untested cancer “cures”, but quickly widened its scope to scrutinise conventional medicine. Richmond was on the committee for some years.

Her skill as a medical journalist made her adept at demystifying evidence and putting it in layman’s terms. A complex character, whose favourite magazine was the Skeptic, she was generous, idealistic and drawn to controversy. She could be tough. Ross said: “I wouldn’t want to get on the wrong side of Caroline. If I were a quack pushing pills to the worried sick, she’d be in there like a bulldog.”

In 1989 a friend, Patrick Collard, died and Richmond wrote his obituary. It took her career in a new direction, and she became a prominent obituarist of doctors and scientists for the BMJ, the Independent and the Guardian for several decades. Richard Smith, editor of the BMJ from 1991 to 2004, described Richmond’s writing as “crisp and to the point with colourful phrases”.

When she had to describe the physiologist William Keatinge, for example, meeting a bear wakening from hibernation, she summed up the situation with a Shakespeare-inspired line: “Exit Keatinge, pursued by a bear.” Describing the process, Richmond said “It’s like portrait painting. Sometimes the writer really captures the subject, which is a wonderful feeling.”

Some of her favourite subjects included the surgeon Norman Shumway, whom she later recalled as “the real modest hero of heart transplantation” and Sir Douglas Black, applauding him “for exposing health inequalities and trying to eradicate them”.

In providing a rounded picture of someone’s life, Richmond was not prepared to gloss over shortcomings or avoid making judgments. In 2003, she wrote an obituary for the BMJ of the founder of Scotia Pharmaceuticals, David Horrobin. She had worked for him and could vouch for his charm and intelligence, but said his research ethics were dubious and, as the promoter of evening primrose oil (the remedy for which she said there was no disease) “he may prove to be greatest snake oil salesman of his age”.

The obituary caused thunderous letters to the BMJ for months and a complaint to the Press Complaints Commission. Smith, as BMJ editor, apologised for causing offence to Horrobin’s family, but defended the piece, saying, “A lot of what our readers want is what I call glorified death notices, but we want serious journalistic pieces that tell stories and do make a judgment on a character.”

She was born Caroline Smith in Leicester. Her father, Cedric, was Anglo-Indian and worked in the civil service, and her mother, Kathleen (nee Meeson), was a secretary. She had an elder brother, Clive. It was not an easy childhood: she did not get on with her father or fit in at school. The family moved to Kensington, London, after the second world war and Caroline went to Richmond county school for girls, from where she was expelled, she said, for being unpunctual, never having the right uniform and making the other girls laugh. But she came across science books in the library and said: “Facts and science became my haven.”

Aged 16, Caroline got a laboratory assistant job at a teacher training college. She studied for A-levels at night school and then a zoology degree at Sir John Cass College in London (now part of London Metropolitan University). Her studies were interrupted by a nervous breakdown but nevertheless she got her BSc and embarked on a neuroscience PhD at University College London. Some of the results of her experiments compared badly with a colleague’s (who she was sure was cheating) and she did not finish the PhD. Instead, she started freelancing for the New Scientist. She also worked for Horrobin in his start-up publishing company in Lancaster for several years.

In the late 1980s she became the UK correspondent for the Canadian Medical Association Journal and contributed to a BBC programme on the history of the NHS and a Granada World in Action programme about rogue doctors exploiting people who believed they had allergies. She also contributed to several books and with Marks co-wrote Insulin Murders (2007).

In 1976, Caroline had married Peter Richmond, but it was not a happy relationship and they divorced two years later, though she kept her married surname. Through Guardian Soulmates she met Jim Edgar in 2010, when she was 68, and they married in 2015. Aside from work, she said her partnership with Jim was one of the three things that gave her great happiness (the others were her cats Thisbe and Horace and her membership of the Chelsea Arts Club).

Richmond lived with ill-health for many years. In 1992, she had surgery to remove the lining of the womb and came round to find the surgeon Ian Fergusson had removed her ovaries and womb, concerned he had found a cancerous lump. She was horrified, referring to it as “a castration”, and complained to the General Medical Council. The surgeon was cleared of misconduct but it was a high-profile case and, as a result, the BMA strengthened their guidelines for ensuring patients gave informed consent to procedures.

In November last year Richmond was made an honorary member of the Medical Journalists’ Association for her work with HealthSense. Very ill from normal pressure hydrocephalus, she nevertheless continued to lobby on health and other issues she cared about. Unhappy that a rose in her garden was called “Mortimer Sackler” (a key player in the Purdue Pharma scandal) she persuaded the RHS to drop the name and it became “Mary Delany”, much to her satisfaction.

Richmond is survived by Jim and her stepchildren Lisa and Ian.

• Caroline Richmond, medical journalist, born 8 April 1941; died 24 December 2023