Abstract: A water soluble extract from nonpathogenic aerobic corynebacteria such as Corynebacterium equi Ko-85 strain, the said water soluble extract having the following characteristics:(a) protein content: 3.9-5.5 mg/ml (on the basis of Bovine Serum Albumin),(b) sugar component: 0.41-0.52 mg/ml (on the basis of glucose),(c) nucleic acid like substance: optical density in 260 nm/280 nm (ratio) of 1.56-1.62, and(d) isoelectric point: 3.75-3.80.The extract possesses an anti-allergic effect, an anti-cancer effect, and an immunopotentiative effect and is particularly useful as an anti-allergic agent.