January is National Blood Donor Month and it's the perfect time to head to a nearby donation center. Giving blood helps hospitals and clinics stock up their blood banks and be ready during a crisis. One blood donation can help save the lives of up to three people, according to the American Red Cross.

But can you donate blood if you've had cancer? What if you've recently traveled to an exotic locale, or if you're a gay man or under 18?

If you'd like to give one of the 15.7 million donations collected by the American Red Cross every year, here's what you should know.

Age: You must be at least 17 years old (or 16 years old with parental consent in some states).

Weight: You must weigh a minimum of 110 pounds. There is no upper weight limit as long as you don't weigh more than the bed/lounge will support.

General health: You must be feeling well on the day you donate. You can't donate blood if you have an active infection or are taking antibiotics for an infection. If you have a chronic health condition such as diabetes, it must be well managed and under control.

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Sexual orientation: The Food and Drug Administration recently lifted the ban on gay and bisexual men donating blood. The ban was replaced with a 12-month deferral policy. Gay and bisexual men must be celibate for one year before they can donate blood. A person cannot donate blood if he or she has ever tested positive for HIV.

Travel: If you traveled outside of the U.S. or Canada in the past three years, the blood donation center needs to review your travels to make sure you weren't exposed to malaria. The American Red Cross might ask that you wait a year after returning from a country where malaria is found.

Medications: Most medications won't disqualify you from giving blood. One exception is prescription blood thinners. If you're taking one, you shouldn't donate because your blood may not clot normally. If you take Accutan (isoretinoin) for acne you'll have to wait a month after your last dose.

Drug use: You should not donate blood if you have ever used needles to take drugs, steroids or anything not prescribed by your doctor.

Tattoos: If you recently got a tattoo, you need to wait 12 months before you can donate blood again.

Pregnancy: You can't donate if you're pregnant. Women must wait six weeks after giving birth before donating blood.

Cancer: If you have cancer, you may be able to donate blood depending on the type of cancer you have and the medications you're taking. If you have or had leukemia or other cancers of the blood, you can't donate blood. If you had certain other types of cancer, you may need to wait a year after the cancer was successfully treated.

STDs: If you have a sexually transmitted disease such as gonorrhea or syphilis, you must wait 12 months after treatment is finished before donating blood.

Heart problems: You'll need to wait six months if you've had a heart attack or an episode of angina or you've had bypass surgery or angioplasty.

Related: 7 Lies You Should Never Tell Your Doctor

If you're not sure about your eligibility you can call the American Red Cross at 1-800-RED CROSS.

Ready to donate ? Find your local Red Cross chapter here.

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Muriel Vega is a writer with a passion for budget travel and staying safe while abroad. A Georgia State University graduate, she has over 6 years of editorial experience and has written for The Guardian, The Atlantic, The Billfold, among other outlets. In her free time, you can find her baking pies, playing with her two dogs and cat, or planning her next vacation. She spends way too much time on Twitter, one of her favorite social media channels. Her favorite safety tip: Make sure you have all the necessary shots before you go abroad.