AbstractThis study was performed to evaluate the relative efficacy of Maharishi Amrit Kalash ambrosia (MAK‐5) and Maharishi Amrit Kalash nectar (MAK‐4) on murine (B‐16) and human (SK‐Mel) melanoma cells in culture. Ethanol extract (EE) of MAK‐5 (EE‐MAK‐5) induced morphological differentiation (enlargement of soma and nuclei and formation of long dendritic processes) and growth inhibition in mouse melanoma cells, whereas EE‐MAK‐5 inhibited only growth in human melanoma cells. Murine melanoma cells were more sensitive (about 3 times) than human melanoma cells in culture to EE‐MAK‐5; the aqueous extract (AE) of MAK‐5 (AE‐MAK‐5) was ineffective in both cells. Boiling EE‐MAK‐5 for 10 minutes or exposing it to light at room temperature for 72 hours did not alter growth‐inhibiting potency. Ethanol extract of another herbal agent, MAK‐4 (EE‐MAK‐4), inhibited growth in human melanoma cells but not in mouse melanoma cells. AE‐MAK‐4 was ineffective for both cells. These results suggest that murine and human melanoma cells respond differently to MAK‐5 and MAK‐4 and that human melanoma growth‐inhibiting agents are present in both EE‐MAK‐5 and EE‐MAK‐4.