There are effective treatments available for a number of sexually transmitted diseases (STDs). Chlamydia, gonorrhea, syphilis, and trichomoniasis can all be treated and cured reasonably easily with antibiotics. However, having your STD treated is not a guarantee that it will never come back. There are several reasons why simply finding treatment for an STD isn't enough. You also have to be careful about your future behavior.

One or more of these can be in play in cases where someone gets treatment for an STD, only to realize they have it again.

common reason for STD recurrence — Verywell / Cindy Chung

Taking the Incorrect Medication

Another reason that treatment can fail is that you're taking the wrong medication. That might happen either because your doctor prescribed the wrong drugs or because you found a way to acquire drugs on your own and chose the wrong ones.

Not all STDs are caused by the same pathogens. Different illnesses require different treatments.

That's why it's so important for your doctor to correctly identify what's causing your infection before she prescribes antibiotics. That's also why you can't just take any random antibiotic and hope it's going to work.

Taking Medication Incorrectly

If your doctor prescribes you antibiotics, it's incredibly important to take the whole prescription. That's true even if you feel better before you're done. Failing to finish your antibiotics might not only keep your STD from being cured. It might also make it far more difficult to treat your STD when your doctor tries to do so next time (antibiotic resistance). This is a serious concern, particularly with certain infections.

Failing to Make Sure Your Partner Gets Treated

If you have a regular sexual partner, it's important to tell them about your infection so they can get treatment, too. Once you've both gotten treated, you have to wait until the treatment has had time to work before you once again start having sex (particularly unprotected sex). Without taking these important steps, it is possible for the two of you to end up passing the STD back and forth indefinitely.

Being Exposed to a New STD

This is a big one. Being successfully treated for chlamydia, gonorrhea, or another STD does not mean that you can't get it again. In fact, many people become infected with STDs over and over again because they continue to have unprotected sex with partners who have untreated STDs.

If you've been treated for an STD and don't want to get another one, the best thing that you can do is change your behaviors to decrease your risk. That means both consistently practicing safe sex and always talking to new partners about risk before having sex.

STD-Specific Concerns

Certain STDs pose additional problems that can make them likely to have an encore. If you've been diagnosed with any of these, it's important to keep the following in mind.

Chlamydia

It is well known that in a significant fraction of people who have been diagnosed with and treated for chlamydia, the infection will come back after treatment. For a long time, it was thought that they were simply becoming exposed again or that treatment was failing. However, research has suggested there may be an additional explanation. Animal models suggest that chlamydia may be able to hide out in the gut and re-emerge. This probably doesn't happen all that frequently. Still, it is another reason why chlamydia can come back after treatment.

Gonorrhea

In theory, gonorrhea is easily treatable with antibiotics. However, antibiotic-resistant gonorrhea has grown so common that it is starting to become a public health crisis. Over time, it has become more difficult to find affordable antibiotics that can consistently, effectively treat gonorrhea. That means people seeking treatment may need to be treated with more expensive antibiotics. They also may need to have their infection tested for susceptibility to treatment or come back after treatment to see if it worked. Either way can lead to substantial costs in terms of both time and effort.

Syphilis

As with the other bacterial STDs, syphilis can be treated effectively. However, a variety of factors have been shown to affect how well treatment works. These include the stage of syphilis that people are in, how often they use condoms, and whether or not they have HIV. In general, it is easiest to treat syphilis when it is caught early, and when people have a healthy immune system. Fortunately, even in other groups, treatment failure is relatively rare.

Trichomoniasis

Around the world, trichomoniasis is the most common curable STD. However, with the standard single-dose treatment, repeat infections occur somewhat frequently. Fortunately, research has shown that recurrence occurs around half as frequently with multi-dose treatments for trichomoniasis. Multi-dose trichomoniasis treatment is now the standard regimen for women with HIV. However, it is available for HIV-negative women as well.

The other issue with treating trichomoniasis is that men are generally not tested (and therefore, treated) for the disease. While infections are generally less serious in men, they do need to be addressed to keep them from re-infecting their female partners.

A Word From Verywell

No one wants to see an STD come back after treatment. Fortunately, most of the STDs that are curable with antibiotics are also preventable by practicing safe sex. Using condoms, dental dams, and other barriers to make your sex life safer is a very effective way to prevent bacterial STDs. However, it's important to use them consistently, and for vaginal, anal, and oral intercourse.

While it's best to practice prevention strategies all the time, if you didn't on an occasion, start back up again next time. STDs aren't necessarily transmitted every time you have sex, so it's never too late to start doing things more safely.