Sexually transmitted diseases (STDs), also known as sexually transmitted infections (STIs), are infections or conditions that can be transmitted through sexual contact. There are dozens of STDs, including bacterial, viral, and parasitic infections. Some of the most common STDs include:

• Chlamydia
• Gonorrhea
• Syphilis
• Genital herpes
• Human papillomavirus (HPV)
• Trichomoniasis

STDs can be spread through vaginal, anal, and oral sex, as well as through intimate physical contact like heavy petting. They can be caused by bacteria, viruses, fungi, or parasites. Many STDs have no symptoms, so people can have an infection but not know it. However, some common symptoms of STDs include:

• Unusual discharge from the penis or vagina
• Sores or warts on the genital area
• Painful or frequent urination
• Itching and redness in the genital area
• Blisters or sores in or around the mouth
• Abnormal vaginal odor
• Anal itching, soreness, or bleeding
• Abdominal pain
• Fever

If left untreated, STDs can cause serious health problems, including pelvic pain, pregnancy complications, eye inflammation, arthritis, pelvic inflammatory disease, infertility, heart disease, and certain cancers. It is important to get tested regularly for STDs if you are sexually active, and to practice safe sex by using condoms and other barrier methods.