[header] How to prevent syphilis [title] Limit your number of sexual partners. [step] If you are sexually active, you can prevent syphilis by limiting your number of sexual partners. Your risk of contracting syphilis goes up with the number of sexual partners you have. 
Sexually active people who have only one partner in a monogamous relationship are safest, as long as neither partner has sex with anyone else. For some people, however, this might be unrealistic.