The total alkaloid fractions of the methanolic extracts of the leaves, ripe fruits, roots, seeds and stem of Solanum pseudocapsicum were subjected to in-vitro cytotoxicity, short-term toxicity and long-term survival studies. All the five fractions exhibited potent activity. The total alkaloid fraction of leaves was found to be the most potent. The HT-29 cell line was the most sensitive to the fractions. The cytotoxic concentration (CTC(50)) values for all these fractions ranged between 0.39-0.91, 0.68-2.8, 0.92-3.56, 4.05-8.2, 3.28-5.65 and 0.95-5.55 microg/ml, respectively for HT-29, RD-228, A-549, HEp-2, B(16)F(10) and Vero cell lines. In short-term toxicity studies, the fractions showed 50% viability at 93-128 microg/ml for DLA cells and 141-189 microg/ml for human lymphocytes. In the long-term survival studies on the cell lines RD-228, HEp-2 and Vero, cells retained their regenerative capacities at concentrations below 8 microg/ml. The total alkaloids of the plant, especially from the leaves merit further investigations to identify the active constituents in animal models.