Tea is brewed by pouring hot water over leaves of the Camellia sinensis plant. This plant is in the Theaceae family of plants. This type of tea is referred to as black tea because the plant has been dried and oxidised before being processed. Green tea is made from the same plant, but it is harvested and processed before the plant is oxidised. White tea is also harvested from the same plant, but is picked when the buds have not opened and are still white.

Red tea, more commonly called rooibos tea, is from a different plant, Aspalathus linearis, which is in the Fabaceae family of plants. This family of plants are commonly referred to as Legumes.

Camomile tea has its own page.

Matcha is a green powder made from ground green tea leaves. If you are allergic to tea you may be more likely to have an allergic reaction to drinks or foods containing matcha as the leaves, though ground, are actually being eaten and digested rather than just being used in bag or leaf form for steeping.

Tea contains caffeine, so this may one of the causes of a perceived allergy. If you have symptoms to tea and coffee you may be intolerant to caffeine rather than allergic to tea leaves.

Tea also contains tannins, the stronger the tea is brewed the more tannins it contains, these are phenolic compounds which can cause symptoms of intolerance in some people.

Contact reactions to tea can be caused by nickel allergy. Nickel is found in most foods, but is in higher concentration in tea leaves. Contact reactions are most likely to affect those who pick or process tea leaves.

Black, white, green and red teas are low in histamine. Some green and white teas are not suitable for people following a low histamine diet as it contains a compound called methylated epigallocatechin gallate (EGCG). EGCG can block the enzyme diamine oxidase (DAO) which breaks down histamine present in the body. Tea does contain putrescine, another biogenic amine found in citrus fruits, chocolate, tea and nuts which people can be sensitive too. It is also found in high histamine foods, so tea is often included in histamine food lists.

All types of tea are low in FODMAP. FODMAP stands for Fermentable oligosaccharides, disaccharides, monosaccharides and polyols. Foods high in FODMAPs can cause symptoms of food intolerance, affecting the gastro intestinal system and this can be mistaken for a true IgE food allergy.

Teas are high in salicylates. Salicylates have the potential to cause worsening of asthma, swelling, itching and hives as well as food intolerance symptoms in people who are sensitive to salicylates.

You can read more about Food Intolerances on the dedicated Food Intolerance Page.

Contact dermatitis is associated with an allergy to one of the many of the compounds in tea leaves.

Tea contains methylated epigallocatechin gallate (EGCG), which can cause asthma, it is most strongly associated with green tea and is referred to as 'green tea asthma'. It is likely that white tea would also have the potential to cause asthma in people who have reacted to green tea.

Red teas are made from legumes, but are so processed that there is no evidence of them causing cross reactions with other legumes.

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