Gastropod mucus has been shown to possess antibacterial and antitumorcidal properties. Melo broderipii and Lambis lambis are two gastropods abundant in the Philippines and claimed to have antibacterial and antioxidant properties but no available data yet on its cytotoxic and genotoxic effects. The aim of this study was to evaluate, for the first time, the cytotoxic and genotoxic effect of mucus from Melo broderipii and Lambis lambis. For cytotoxic effect determination, microscopic observation for cell arrest, cell bursting and morphological distortion of the developing sea urchin embryo and quantification of affected zygotes were conducted. For genotoxic effect determination, root length measurement and microscopic observation for chromosomal aberration of onion root tip were conducted. Results for cytotoxic effect showed that Melo broderipii mucus (80% v/v) test solution (TS) had 70% cytotoxic activity while Lambis lambis (80% v/v)TS had 65% cytotoxic activity. Cell arrest (40%) was the most prominent parameter for both test solutions. For genotoxic effect, Melo broderipii mucus (100% v/v) elicited root growth of 0.244 cm while Lambis lambis mucus (100% v/v) exhibited root growth of 0.367 cm. Bridges and fragments of chromosomes were observed in 100% TS of Melo broderipii while vargrants and binucleated chromosomes in 100% TS of L. lambis. Alkaloids, terpenes and proteins present in the mucus of Melo broderipii and Lambis lambis account for the cytotoxic and genotoxic effects.