Men who eat too much liquorice could risk damaging their sex lives, according to a study.
Liquorice is used in many products, including sweets
Researchers from Iran have found that liquorice - used in sweets, chewing gum, toothpastes and herbal remedies - can lower testosterone.
Low levels of testosterone can affect libido and mood and may even increase the risks of sexual problems.
Speaking at the British Pharmaceutical conference in Harrogate, researchers urged men to be aware of the risks.
Dr Mahmoud Mosaddegh and colleagues at the Shaheed Beheshti University of Medical Sciences based their findings on a study of 20 healthy men.
They were all given 1.3g of dried liquorice root extract everyday for 10 days.
The extract contained about 400mg of glycyrrhizic acid, which gives liquorice its distinctive taste.
The extract is used in popular herbal remedies. Manufacturers claim it can relieve cold, flu and allergy symptoms and may even help people with chronic fatigue or ulcers.
It is also found in smaller quantities in confectionery, toothpaste and some herbal teas. Cigarette and drugs manufacturers sometimes use it to improve the taste of their products.
Some brands of chewing gum can contain 24mg of glycyrrhizic acid while some herbal teas can contain up to 450mg per litre.
A report by the European Commission published earlier this year suggested that people should not consume any more than 100mg of glycyrrhizic acid a day.
The Iranian researchers took blood samples from the men involved in their study.
They found that the men all had significantly lower levels of testosterone than they would normally expect.
The findings backs up a previous study published in 1999. It also reported lower testosterone levels in men taking liquorice.
However, other studies have found no such link.
Nevertheless, Dr Mosaddegh said men should avoid consuming large amounts of liquorice and in particular liquorice herbal remedies.
"Liquorice root extract is a popular treatment, traditionally used for treatment of gastrointestinal disorders but until further data are available we would advise caution in use of the extract."
But he added: "More research is needed to assess the hormonal effects of liquorice."