If life was fair, it would be impossible to catch anything remotely bad from a kiss.

But in addition to things like the common cold and the flu (seriously, get vaccinated, people), it is actually possible to contract various illnesses from a make-out session. That includes a couple of s_xually transmitted ones.

Here, doctors explain potential infections you can get from kissing, along with exactly what you need to know to stay as safe as possible.

1. Herpes

Herpes may be incurable, but it doesn’t make you a pariah. In fact, it kind of makes you normal.

Around two-thirds of the world’s population under the age of 50 has herpes simplex 1 (HSV-1), which is known as the oral kind of herpes, according to the World Health Organization.

The thing about HSV-1 is that it sometimes creates cold sores in and around the mouth. “If you’re kissing someone with lesions in their mouth, mucous membranes make herpes easy to transmit.

So, if someone you’re kissing has HSV-1, they could give you the virus (even if they aren’t currently experiencing an outbreak, a phenomenon known as ‘asymptomatic shedding’ means they can still transmit it.

And if they go down on you, they could transmit the virus to your genitals.

If you or your partner has cold sores, over-the-counter medications like Abreva can shorten the outbreak.

There are also antiviral medications like Valtrex that people can take on a regular basis to prevent outbreaks from occurring.

2. Syphilis

“Syphilis is a highly infectious condition, and one of its hallmarks is the development of sores in the mouth,” board-certified ob/gyn Antonio Pizarro, M.D., reveals.

The sores, which are usually round and open, “combine to make syphilis transmissible through kissing,” says Pizarro.

Kissing isn’t the most common way to transmit syphilis—oral, an_l, and v_ginal s_x still rank higher. But syphilis rates are currently on the rise, according to the CDC, so it’s good information to have.

If you or your partner has syphilis-related sores in your mouth, they (and the virus itself) should clear up with the help of doctor-prescribed antibiotics.

So, what about other STIs? While the chances of passing infections like gonorrhea, chlamydia, and HIV through saliva aren’t usually worth worrying about, that changes if one of you has a cut or sore in your mouth.

“Any time there’s an open sore and/or blood present, theoretically an infection could be transmitted orally,” says Pizarro.

3. Meningitis

Some meningitis is caused by bacteria while other cases come about because of viruses (including the herpes virus).

Close contact with a person who has viral meningitis can result in you getting the virus, but it’s unlikely to actually turn into meningitis, according to the CDC.

Bacterial meningitis is usually the kind associated with outbreaks because the bacteria can be spread through close contact, including kissing, but unlike with the viral variety, the bacteria is more likely to cause meningitis in the host, says Carpenter.

Symptoms include a stiff neck, fever, and headache, according to the CDC.

“If we are aware of an outbreak, we will give people who have had close contact with the [infected person] antibiotics to protect them.

4. Infectious mononucleosis

Ah, the so-called “kissing disease”! It definitely deserves its nickname, because mono is caused by a virus that is easily transmitted through kissing.

One of its trademark signs is intense fatigue, although others include a sore throat and swollen lymph nodes.

According to Mayo Clinic, “treatment mainly involves bed rest, good nutrition and drinking plenty of fluids,” so that’s basically the only potential benefit of getting mono.

5. Gingivitis

Kissing doesn’t just involve swapping spit—although, how unsexxy does that sound when you’re not actually doing it?—it also includes exchanging bacteria with the other person.

Depending on both of your oral healthcare habits, that bacteria can cause gingivitis, which is a mild form of gum disease. (It can also cause cavities.)

“We each have our own natural bacterial flora in our oral environments. When someone has poor hygiene, certain bacteria in and around the gum tissue can become overwhelming,”.

They can pass that bacteria to you via kissing, which can potentially result in the typical inflamed, red gums that signal gingivitis. The best way to protect yourself is by maintaining excellent oral healthcare (i.e. brushing twice a day and flossing before bed) so no matter what kind of bacteria someone’s introducing into your mouth, you’re on it before it can grow out of control.