Molluscs, such as snails and slugs, can be detrimental to various crops and plants, causing significant economic losses. The control of these phytophagous molluscs often relies on the use of synthetic molluscicides, which can have adverse effects on the environment and human health. Therefore, there is a growing interest in exploring natural alternatives for mollusc control. This study aimed to investigate the active molluscicidal components present in various organs of Euphorbia helioscopia from Morocco. A preliminary phytochemical screening was conducted, revealing the presence of polyphenols in leaves, flowers, and stems, while saponins were found exclusively in the roots. Alkaloids were absent in all plant parts. The highest yield of polyphenols was obtained from the stems, followed by flowers and leaves. The extraction of saponins resulted in a lower percentage yield. The molluscicidal activity of the extracts was evaluated against two terrestrial phytophagous molluscs, Theba pisana and Arion hortensis, following World Health Organization (WHO, 1965) guidelines. The results showed that polyphenols from E. helioscopia stems exhibited the highest toxicity against Arion hortensis slugs, followed by polyphenols from flowers, saponins from roots, and polyphenols from leaves. Similarly, for Theba pisana snails, the most toxic extracts were polyphenols from stems, followed by polyphenols from flowers, polyphenols from leaves, and saponins from roots. These findings highlight the potential of E. helioscopia extracts as natural molluscicides, demonstrating their effectiveness against the tested molluscs.