Solanum lycocarpum St. Hill (Solanaceae) is a native shrub very common in the Brazilian savanna. The fruit of this plant contains steroidal glycoalkaloids that may disrupt the endocrine system. Because this plant is employed in folk medicine for the management of diabetes, obesity and decreasing cholesterol levels, the present study determined the possible toxic effects of exposure to S. lycocarpum fruit from weaning (21 days old) until adult age (8 weeks of treatment) in male and female rats. In male rats, the plant reduced weight gain, while few significant differences were observed in female animals. Slight significant differences were observed in food and water consumption and in hematological parameters in treated rats. Reductions in adrenal gland, spleen, heart, kidneys and thymus weights of treated males were observed, while increased relative weights were detected in the heart, epididymises, lungs, seminal vesicles, and testicles. In females, no differences were observed in organ weights and few differences were observed in relative weights of some organs. The histopathologic study showed no alteration between groups. Serum biochemical parameters showed triglyceride reductions in treated animals of both sexes; in females, an increase in albumin and alanine aminotransferase levels and a reduction in total protein levels were noted. The present data therefore demonstrate sex-related differences in S. lycocarpum toxicity.