Phuk-waan-ban, Euphorbiaceae Sauropus androgynus (Linn) Merr, belongs to the family Euphorbiaceae, which is the same as the rubber tree, Euphorbiaceae Hevea brasiliensis. The young leaves are edible. To the best of the authors knowledge, this is the first report of anaphylactic reaction to Phuk-waan-ban in latex allergic patients. Contact urticaria and anaphylactic reactions to latex-containing rubber products are being recognized with increasing frequency in all kinds of medical disciplines. The prevalence and incidence are both increasing. Recently, a number of reports have been published describing anaphylactic reactions to food items in patients with latex allergy. The authors present a patient with occupational natural rubber allergy who developed an anaphylactic reaction with urticarial rash 20-30 minutes after ingestion of phuk-waan-ban. The diagnostic work up showed specific IgE to latex (CAP class 3). Positive skin prick tests to latex and cooked and raw phuk-waan-ban crude extract confirmed allergic reactions. Moreover, the cross-reaction between phuk-waan-ban and latex can be confirmed by using IgE inhibition test.