Toxicity
Excessive consumption of liquorice or liquorice candy is known to be toxic to the liver and cardiovascular system, and may produce hypertension and oedema. In occasional cases blood pressure has increased with excessive consumption of liquorice tea, but such occasions are rare and reversible when the herb is withdrawn. Most cases of hypertension from liquorice were caused by eating too much concentrated liquorice candy. Doses as low as 50 grams (2 oz) of liquorice daily for two weeks can cause a significant rise in blood pressure.

The European Commission 2008 report suggested that “people should not consume any more than 100mg of glycyrrhizic acid a day, for it can raise blood pressure or cause muscle weakness, chronic fatigue, headaches or swelling, and lower testosterone levels in men.” Haribo, manufacturer of Pontefract cakes, stated: “Haribo advises, as with any other food, liquorice products should be eaten in moderation.” A 56-year-old Yorkshire woman was hospitalized after liquorice overdose (200 grams or 7 oz a day), which caused muscle failure. The hospital restored her potassium levels, by intravenous drip and tablets, allowing her to recover after 4 days.

Comparative studies of pregnant women suggest that liquorice can also adversely affect both IQ and behaviour traits of offspring.

The roots and/or rhizomes of Glychyrrhiza uralensis, G. glabra and G. inflata, and commercial licorice specimens from various regions or countries were analyzed by high-performance liquid chromatography (HPLC), and classified into three types based on their phenolic constituents. i) Type A: The roots and rhizomes of G. uralensis, commercial licorice specimens from northwestern region of China (Seihoku-kanzo) and from northeastern region of China (Tohoku-kanzo) in Japanese markets, and also several licorice specimens from Chinese markets. They contain licopyranocoumarin (6), glycycoumarin (7) and/or licocoumarone ( , which were not found in G. glabra and G. inflata. ii) Type B: The root and rhizome of G. glabra, and the licorice specimens imported from the Soviet Union and Afghanistan. They contain glabridin (9) and glabrene (10), which were not found in the samples of the other two Glycyrrhiza species. A root sample of Glycyrrhiza species from Turkey also contains 9 and 10. iii) Type C: The root sample of G. inflata. They contain licochalcones A (11) and B (12), which were not found in the samples of the other two Glycyrrhiza species. Commercial licorice specimens obtained in Japan, which were imported from Sinkiang of China (Shinkyo-kanzo), and some licorice specimens obtained from Chinese markets, have also been found to contain 11 and 12. The phenolics 6-12, characteristic constituents of types A, B or C, were not found in a specimen of cortex-free licorice from a Japanese market (kawasari-kanzo). Extracts of some licorice specimens of types A and B, and all of the licorice specimens of type C inhibited 40-56% of the xanthine oxidase activity at the concentration of 30 micrograms/ml. Extracts of some licorice specimens of types A and B also showed inhibitory effects on monoamine oxidase (44-64% inhibition, at the concentration of 30 micrograms/ml), which were slightly weaker than that of harmane hydrochloride.
[ 01 August 2002: Message edited by: C21H23NO5 ]

from Foods to Avoid with MAOIs Miscellaneous
Soy sauce
Brewers yeast (Bread, cake, cookies etc. are OK as they do not contain brewers yeast)
Marmite
Licorice
Over one ounce of chocolate