The new phenolic compound, 3,5-dihydroxy-4-methoxy phenethyl alcohol, named alphitol, and betulinic acid were isolated from the bark of Alphitonia zizyphoides. The chemical structure of alphitol was determined by mass spectrometry in combination with one and two dimensional NMR, including HMBC. Both compounds inhibited prostaglandin biosynthesis in vitro, alphitol with an IC50 value of 0.66 mM, which is of the same magnitude as acetyl salicylic acid.