AbstractGas chromatographic analysis of natural pyrethrins in insecticidal pyrethrum extract and in insecticide formulations is achieved by on‐column injection with hydrogen as carrier gas under constant flow and programmed pressure conditions. Short thin‐film fused silica capillaries (DB 5 and DB 1701) coupled to retention gaps separate the pyrethrins (cinerin I and II, jasmolin I and II, and pyrethrin I and II) and their analogue S‐bioallethrin (Esbiol) in less than twelve minutes at temperatures below 210°C without any discrimination, degradation or isomerization of thermally labile pyrethrin I and II. With S‐bioallethrin added as internal standard, spray and powder formulations are extracted with ethyl acetate and analyzed by gas chromatography with flame ionization detection for pyrethrum constituents, for other pyrethroids such as tetramethrin, cyphenothrin, cypermethrin, and for the commonly used synergist piperonl butoxide.