We analyzed hyperactivation and fertilizing capacity of the sperm of Tetrapygus niger "black sea urchin" in the presence of β-caryophyllene. β-caryophyllene obtained from extracts of Piper nigrum "black pepper" and synthetic β-caryophyllene donated by the Biosciences Institute of the University of Sao Paulo, Sao Paulo, Brazil, was used. Tetrapygus niger spermatozoa pretreated with the extracts of synthetic β-caryophyllene (β-caryophyllene A) and β-Caryophyllene from black pepper (β-caryophyllene B) were used to study the eff ect of this molecule on sperm hyperactivity (mean velocity and percentages of progressive and continuous movement) and the fertilizing capacity (percentage of fertilized ovules). Th e average values of the sperm head area in the control and in the treatments with βcaryophyllene A and β-caryophyllene B were: 33.8; 32.33 and 33.59 um 2 , respectively, indicating the homogeneity in the sample and that this was not infl uenced by the sesquiterpene. In the presence of β-caryophyllene A and B, the average speed observed was decreased by approximately 30 and 20 um/s, respectively, with respect to the control. Th ere are signifi cant diff erences between the control and the treatments with β-caryophyllene A and B, but not between the two treatments with β-caryophyllene. Th e progressive movement of the sperm was also aff ected. While all the sperm of the control group showed rapid progressivity; in the treatment with β-caryophyllene B only 40% presented this characteristic and in the treatment with β-caryophyllene A 100% were progressive slow. On the other hand, the β-caryophyllene B produced a slight decrease in fertilization (96.76% of fertilized ovules) and in the presence of β-caryophyllene A, this was reduced to 79.50% with respect to the control group. A possible mechanism to explain the eff ects observed in this study would be the ability of β-caryophyllene to activate inhibitory G proteins as reported in other studies.