The present study aimed to assess the safety issues of supplying kidney bean lectin extract early in life to piglets. Four litters totalling or 30 piglets were used. On postnatal day (PD) 10–11, thirty piglets were divided into 3 experimental groups (T1, T2, and T3), each consisting of 10 animals. On PD 10 or 11, group T1 (control) received water. Groups T2 and T3 received, respectively, a dose of 640 (recommended) and 6400 haemagglutination/piglet (10 x recommended) of kidney bean extract orally in a water suspension. On PD 42, all of the pigs were euthanized, and 6 piglets from each group were randomly taken for necropsy, sampling tissue for histology and bacteriological analyses of the lower gut. Blood was withdrawn before euthanasia for haematology and biochemistry. There were no significant differences in mortality, feed intake or body weight gains among the groups. All examined blood parameters were within the physiological range. No significant effects of the two doses of kidney bean extract on tissue morphology were observed in the post mortem inspection and histology. No significant differences among the groups in the number of aerobic and anaerobic bacteria were found. Concluding, a one-month tolerance study with the recommended and 10-fold recommended dose of kidney bean extract revealed no negative effects on piglet health or performance.