The extraction of altrenogest with acetonitrile from sesame oil is not an easy task due to the formation of a stable emulsion. The problem of extracting more than 99% of altrenogest from sesame oil with acetonitrile was solved. The optimal ratio of extractant to extractor was established. This approach allowed for a quantitative analysis of altrenogest in sesame oil solutions by HPLC/MS. A generalization of the proposed approach to cases of altrenogest extraction from stable emulsions was discussed.