You’re a conscientious person reading a conscientious science publication, so you probably know that you’re supposed to finish the entire course of antibiotics a doctor prescribes you—even if you’re already feeling better. You may have even found an expired, half-full bottle of amoxicillin in a friend’s medicine cabinet, and shuddered to yourself at their irresponsibility.

If you’re that type of person, I have some bad news: Your friend was probably right, and you are, in fact, wrong.

In 2023, infectious disease experts published a review looking back at 25 years of random controlled trials (more than 120) investigating short and long courses of antibiotics. They found that short courses were just as effective as long courses for everything from routine urinary tract infections to more serious ailments, like pneumonia. If anything, because many antibiotics come with annoying side effects and dietary restrictions, an abbreviated treatment schedule might be preferable.

“What about antibiotic resistance?” you may be wondering. It turns out that shorter courses may actually decrease antibiotic resistance. Under the old regime, it was thought that you needed to take every pill to wipe out every last trace of bacteria, otherwise a ragtag band of survivors who’d adapted to the drugs could stage a comeback.

Read more: “Medicine Is Going Viral”

Fortunately, it turns out, this also isn’t true. “That idea is rather based on urban legend,” authors of an editorial that appeared in an issue of Clinical Microbiology and Infection alongside the review wrote. “The longer patients and the environment are exposed to antibiotics, the greater the selective pressure driving resistance.”

Don’t beat yourself up too much, though—it’s not your fault. Doctors, public health officials, and scientists have recommended taking all your prescribed antibiotics since the 1940s. And, according to a new study published in Open Forum Infectious Diseases, you’re in good company.

Public health and disease experts surveyed over 1,400 adults and asked them about their attitudes toward taking antibiotics. Nearly 90 percent of respondents said it was always best to take the full course of antimicrobial meds, even when feeling better. (Of course, that doesn’t mean they always followed through.) Additionally, most people (around 60 percent) actually preferred a longer course of antibiotics to a shorter one for something like pneumonia. In open-ended responses, these long-coursers thought more pills equaled more effectiveness and expressed the desire to be “better safe, than sorry.” Which seems reasonable!

So how do we overcome the (apparently very successful) public health messaging to always take all your antibiotics?

According to the team, it starts with doctors. Physicians can avoid simplistic long versus short messaging and acknowledge the reality that we will occasionally, through science, learn new things and apply them.

“Evidence is growing and guidance is evolving on antibiotic use, which is a normal process and a good sign that we’re working to improve how we provide care,” study author Alistair Thorpe of the University of Utah explained in a statement. “Our knowledge about how best to use antibiotics has changed, but it’s changed because we’re learning more, and it’s important that we make sure we are communicating this well to the public.”

Now go make up with the friends you shunned for not taking all of their medicine.

Lead image: Line Galaxy and Mariia / Adobe Stock