If you’ve ever taken a trip to the ER, you know that mere hours in the hospital can take a toll—on your bank account. The fact is, even seemingly minor injuries and ailments can put a major dent in your finances…one that often isn’t revealed until the bill shows up in your mailbox.  Among the most expensive ER offenders? Urinary tract infections, or UTIs, which affect around half of all women at some point in their lives. A recent review of over 8,000 ER visits found that the infections were second only to kidney stones in expense. Treating a UTI in the ER, it turns out, costs patients anywhere from $50 to—wait for it—$73,000.  Though the review doesn’t specify, the upper limit of that range probably represents UTIs that have progressed into kidney infections, which can be extremely dangerous, says Lisa Dabney, MD, a New York City urogynecologist. Fortunately, such cases are quite rare, Dr. Dabney says, and typical UTIs will clear up quickly if treated. Your best bet? Obviously, it’d be avoiding the infections altogether. Follow Dr. Dabney’s tips to do just that: Keep it clean. UTIs occur when bacteria gets into your urinary tract or bladder, and are often triggered by sex. The easiest way to avoid a UTI, hands down: pee after sex. Every. Single. Time. “Flushing out your system is the best way to keep infections from forming, so drinking lots of water before and after sex can help too,” Dr. Dabney says. You can also stave off the invasion of bad bacteria by wearing cotton underwear and changing out of wet workout clothes or bathing suits ASAP. Cut out irritants. If you experience frequent and painful urination more than twice a year, a UTI might not be the problem. “Many women think they’re just prone to bladder infections, but they actually have a condition I call painful bladder syndrome, in which certain things make urination more painful,” Dr. Dabney says. Your morning brew or OJ may be to blame: both acidic drinks are known bladder irritants. Before you reach for the antibiotics, eliminate those drinks and stick to water—and lots of it—to cleanse your system. See your doctor. The ONLY way to obtain proper diagnosis is to bring a urine sample to your doctor. “If a patient comes in for a culture and it turns out to be a UTI, a round of antibiotics is needed to treat the infection,” Dr. Dabney says. “But if it’s not a full-blown UTI, symptoms will go away on their own, and any antibiotics would be overkill.” And FYI: If your gyno or primary care physician is prescribing antibiotics over the phone, she could be saddling you with meds you don’t need to take.  Questions? Comments? Contact Prevention’s News Team.