Objective. To determine the effect of the Croton lechleri lyophilized extract gel on root pulp tissue of pulpotomies performed on Oryctolagus cuniculus. Methods. Thirty-two two-month-old male New Zealand rabbits race, were randomly assigned into four experimental groups: a) control, b) formocresol, c) 1% Croton lechleri and d) 2.5% Croton lechleri. Four pulpotomies were done on each animal. Clinical variables (abscesses, tooth mobility and infections) and histopathological variables (fiber formation, pro-inflammatory cell and regenerative cell number) were analyzed after 1,7,15, and 30 days. Results. No clinical signs were evident in all experimental groups evaluation at any time period. In the first day histopathological evaluation, there were abundant presence of capillaries in all control group samples and half of formocresol ones, while 1% Croton lechleri and 2.5% Croton lechleri gro...