Objective: To monitor the effects of genetically modified cottonseed on nutritional status, physiological and biochemical sub-chronic index in rats.
Methods: A total of 140 six to eight-week-old SPF SD rats(male and female,half) were randomly divided into 7 groups,continuously feeding the forage containing 5%,2.5% and 1.25% normal cottonseed and transgenic cottonseed as well as basal forage for 30 days,and then measuring indicators of body weight,food efficiency,blood routine and blood biochemical parameters. 
Results: All the animals grow well and there is no poisoning and dead phenomenon during experimental time.Indicators between experimental and control group show no significant difference(P&amp;#8805;0.05).
Conclusions: The study did not find genetically modified cotton seeds has sub-chronic toxicity in experimental animals.