L-368,899 hydrochloride is a potent, non-peptide oxytocin receptor antagonist. L-368,899 hydrochloride has shown a 40-fold selectivity over Vasotocin V1a and V2 receptors. L-368,899 hydrochloride has been shown to antagonize oxytocin-induced uterine contractions in vitro. L-368,899 hydrochloride is a useful tool for investigating the role of oxytocin, and studies in primates have shown L-368,899 hydrochloride to reduce a number of behaviours such as food sharing, sexual activity and caring for infants. L-368,899 hydrochloride is also known as L-368899 free base, (S)-2-amino-N-((1S,2S,4R)-7,7-dimethyl-1-((4-o-tolylpiperazin-1-ylsulfonyl)methyl)bicyclo[2.2.1]heptan-2-yl)-4-(methylsulfonyl)butanamide, and 1-(((7,7-dimethyl-2(S)-(2(S)-amino-4-(methylsulfonyl)butyramido)bicyclo[2.2.1]-heptan-1(S)-yl)methyl)sulfonyl)-4-(2-methylphenyl)piperazine.