Does drinking onion juice prevent, treat prostate diseases?


A message shared with the FactCheckHub via WhatsApp on April 20, 2021 claimed that onion juice can prevent and treat prostate diseases.

The message which has a call to action “share it to our men” is titled, ‘Onion remedy for prostate’.

It directed men of all ages to drink a 33cl – equivalent to a generic soda can – of onion juice,  three times in six weeks, and it should be repeated after 10 years.


Drinking a glass of onion juice three times in six weeks prevents, treat prostate diseases.

A claim shared on social media that drinking onion juice will treat and prevent prostate diseases.


This claim is FALSE; there is no evidence that onion juice taken in such dosage is effective against the prevention and treatment of prostate related ailments.

An online search gives a potpourri of different self-help remedy using onion, while it has some benefits to the human health, according to a 2002  study published in Phytotherapy Research, there is still insufficient evidence on it effect in the prevention and treatment of prostate diseases.

In addition, Martin Igbokwe, a Urologist and Kidney Transplant Surgeon, noted that, onion being a natural vegetable has some health benefit, but he was not aware of such of benefit in relation to the prescription in the claim.

“As doctors, we only do evidenced based medicine. Using onion juice [to prevent and treat prostate disease]  is not scientifically proven. So, it is not true from the urological perspective”, Uyobong Brown, a Senior Registrar at the Division of Urology, National Hospital, Abuja  (NHA) in Nigeria told The FactCheckHub.

Medical doctors working in the Urology field spoken to by The FactCheckHub concurred with Uyobong.

Does prostate accumulate toxins due to urine and semen which passes through the urethra?

Furthermore, the circulated post also claimed that “from 25 years, the prostate accumulate toxins due to urine and semen which passes through the urethra”.

Medical experts dismissed this claim.

“It is not true.  The prostate does not do that. The prostate is an organ that helps in reproduction. It aids the reproductive process. It doesn’t accumulate toxins”, Orbih Osilama a medical doctor with the Urology Division of the NHA told The FactCheckhub.

Osilama advised against consuming unregulated medication. It can lead to other ailments.

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Prostate diseases

A prostate is a gland in the male reproductive system which produces fluid that carries sperm. The diseases are in a spectrum, It can be benign or malignant, Uyobong Brown explained.

Benign prostate diseases range from normal infections to prostate enlargement (Benign prostatic hyperplasia, BPH), while the malignant is the prostate cancer, he noted.

The medical doctor explained that a benign enlargement (BPH) which can occur as men get older does not mean a patient has cancer or raises the risk as “studies have shown size increment does not correlate with symptoms”.

He advised men who are 50 years and above to go for regular screening, while noting that there is an increased likelihood  for men who have a family history of it.

In 2020, The FactCheckHub debunked social media posts claiming that consuming onion and garlic cures COVID-19.

Studies on onion and effect on prostate diseases

A 2004 study published in peer-reviewed British Journal of Cancer suggests that regular consumption of garlic and onion show promising signs of possessing chemopreventive activity in patients with prostate cancer.

Another study published in 2007 also found out that men with prostate enlargement (BPH) typically ate less garlic and fewer servings of onions per week than those without it. The study however pointed out some weakness which include not taking into account changes in diet over time.

In a population based study in Shanghai, researchers found out that men who had a higher intake of total Allium vegetables had a reduced risk of prostate cancer than those who took less. Allium vegetables are garlic, scallions, onions, chives, and leeks.

However, the research also found out that “Men in the highest intake categories of chives and onions experienced nonsignificant risk reductions”.   This and like the previous studies cited implies that onion showed promise when combined with other vegetables unlike as claimed in the WhatsApp message.

Onion did, however, show promise when studies were done on rats here and here.

In conclusion, there is no sufficient evidence yet that onion is effective against the prevention and treatment of prostate related ailments.

Furthermore, studies carried out in relation to onion and prostate diseases generally used regular intake of the vegetable than the thrice in 10 years prescribed in the circulated claim.


The claim that drinking a glass of onion juice three times in six weeks and repeating it after 10 years prevent and treat prostate diseases is FALSE.

Notes: The report was updated on April 24, 2021 to reflect studies done around onion and prostate diseases. 


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