A new hepatotoxic octapeptide, Lophyrotomin, was isolated from the larvae of sawfly Lophyrotoma interrupta. The isolation involved extraction with boiling MeOH-H₂O (9:1), followed by purification via polyamide, silicic acid, Sephadex G25 super fine, and Whatman CC41 column chromatography, and final isolation by ascending Silica-gel G chromatography. Structural analysis using amino acid analysis, mass spectrometry, and proton magnetic resonance spectroscopy showed Lophyrotomin has the structure C₆H₅CO-ALA-PHE-VAL-ILEU-ASP-ASP-GLU-GLN. The approximate LD₅₀ was 2 mg/kg in mice via intraperitoneal injection. Clinical symptoms of poisoned animals included incoordination, loss of appetite, muscle trembling, and emaciation, with primary liver damage observed post mortem. Cattle only ate larvae in certain 'toxic' areas, suggesting an attractant property produced only in these regions, whose nature remains undetermined.