Bertrand Peter Allinson MRCS LRCP (12 August 1891 – 1 April 1975) was a British physician, naturopath and vegetarianism activist.

Allinson was the son of Thomas Allinson and brother of Adrian Allinson.^[1][2] He was raised as a vegetarian and studied medicine. Allinson qualified MRCS and LRCP in 1914 from the University College Hospital.^[3] He was a Captain in the Royal Army Medical Corps (1916–1920).^[3] He was a physician at the British Hospital for Mental and Nervous Diseases.^[1]

Allinson was an anti-vaccinationist and anti-vivisectionist. He opposed the use of pharmaceutical drugs which he believed hindered the "automatic cleansing process".^[1] Allinson wrote articles supportive of naturopathy. He was vice-president of the National Anti-Vaccination League.^[1]

Allinson was a physician at the Nature Cure Clinic, a naturopathic hospital which promoted vegetarianism and animal welfare causes such as anti-vivisection.^[4] The Nature Cure Clinic opened in 1928 at an apartment in Baker Street.^[5] In 1940, the out-patient building was destroyed by bombing and the Clinic moved to Allinson's house in Dorset Square. After the war, the Clinic moved to Oldbury Place.^[5]

He was treasurer of the London and Provincial Anti-Vivisection Society.^[6] His daughter Sonya Madeleine Allinson was an artist.^[7]

Allinson stated that fruit juice fasting, a strict vegetarian diet and naturopathic practices such as hydrotherapy and osteopathy could be used to prevent and cure many diseases including cancer, hypertension and rheumatism.^{[6][8][9][10]} He opposed the consumption of alcohol, coffee, meat, processed sugar, tea, white bread and promoted a vegetarian diet of raw fruit, nuts, salads, dairy products and whole grains.^[10] He described alcohol, coffee and tea as injurious to the functions of the body.^[11] Allinson recommended persons between the ages of 25 and 55 to take two meals per day and after that age one meal per day in the afternoon.^[11] Allinson was vice-president of East Surrey Vegetarian Society.^[12]

Allinson was vice-president of the International Vegetarian Union (1958–1963) and President of the London Vegetarian Society (1922–1962).^[13][14]

• Mice and Men: Part 1, Mice and Men: Part 2 (The Starry Cross, 1922)
• Meat in the Child’s Dietary (The British Medical Journal, 1935)
• The Diet of the Future (Croydon Vegetarian Society, 1942)
• Diet and High Blood Pressure (The Vegetarian Society, 1947)
• Status of Naturopathy (The British Medical Journal, 1951)
• Nature Cure (The British Medical Journal, 1952)