Type and frequency of early reactions (ER) were studied in 24 children aging 2-14 years victims of snake bites who received pretreatment with histamine antagonists H1 (dextrochlorfenirarnine) and H2 (cimetidine or ranitidine) and hydrocortisone from 1989 to 1993. None of them had atopy nor received any type of anti-venoms(AV) and antitoxins before. Of 24 children, 15 received bothropic AV (ER in 5), 7 crotalic AV (ER in 5), 1 crotalic plus crotalic-bothropic AV, and 1 elapidic AV (ER in 1). In 3 children severe early reactions were observed and they were classified as severe crotalic accident. Results suggest that pre-treatment did not offer safety protection at the appearance of early reactions.