When green pit vipers (GPV), which are common venomous snakes in Thailand, bite humans they cause coagulopathy as well as local tissue oedema. The use of steroids to reduce such oedema is controversial. The role of low, oral doses of prednisolone in the treatment of GPV bites in children has therefore now been assessed, in a randomized, double-blinded, placebo-controlled, clinical trial in Bangkok. Overall, 43 children aged 3-15 years, each with a recent GPV bite to one limb, were randomly assigned to receive oral prednisolone (1 mg/kg.day) or placebo for 3 days, without antivenom or prophylactic antibiotics. The degree of limb oedema was assessed, immediately before the first dose and then daily, by measuring the limb circumference around the fang marks. By 72 h post-bite, both treatment groups showed significant decreases in the level of their limb oedema. Since, at each time-point, the patients in the two groups showed similar levels of limb oedema (and of reduction in such oedema), there appeared to be no benefit from the use of the prednisolone.