The present invention refers to a composition for obtaining a natural bioactive for oncologic therapies based on Andrographis paniculata, whose excipient is phosphoryl ethanol amine, and optionally carbonates. The function of the composition is to assist treatments of several types of cancer, and it may be administered as an auxiliary adjuvant in oncologic therapies. Since it consists of diterpenoids, flavonoids and polyphenols as the main bioactive components, it has an anti-inflammatory, antiviral, antibacterial, antioxidant, antiparasitic, antispasmodic, antidiabetic, antipyretic, nematocidal, immunomodulatory and immunostimulatory action. The composition for obtaining a natural bioactive for oncologic therapies comprises: Active principle: Andrographis paniculata, and Excipient: phosphoryl ethanol amine. Optionally, the excipients are comprised of: Phosphoryl ethanol amine-Calcium Carbonate; and Magnesium Carbonate.