Medically Reviewed

Probiotics Side Effects: Should You Be Worried?

Like most supplements, probiotics do come with concern of side effects. While side effects are rare and mild, a discussion of these effects is still warranted.

Probiotics Side Effects

Your body contains both “good” and “bad” bacteria and other microorganisms. The good and the bad bacteria are normally kept in balance within your body. This balance is disrupted, however, when the good bacteria decrease or the bad bacteria increase. Probiotics may help to preserve the balance that your body is fighting to maintain.

As one of the fastest growing supplements in terms of popularity, the benefits of probiotics are quickly being revealed. But there may be some side effects that accompany these benefits. For most people, these side effects are minor (if they occur at all). Regardless, it is important to discuss the side effects that a person may experience after taking a probiotic.

How do probiotics work?

As mentioned briefly above, probiotics replenish the good bacteria in your body. Your body thrives when it is in balance (i.e. when good and bacteria are balanced out). Therefore, if the good and bad bacteria in your system become imbalanced, negative consequences may result

Adding good bacteria to your system could offset the imbalance that this intruding bacteria caused. The good bacteria that are found in probiotics may offer many benefits. One of the most important benefits is the immune system support that good bacteria provide. Other benefits include improved inflammatory responses, food digestion and absorption. H3: How effective are probiotics?


As probiotic research has expanded, so has the public’s interest in taking probiotics. Does the attention that probiotics are getting match their efficacy? Luckily, the answer is yes. These benefits include immune Support, improvement in bowel movement patterns and fecal microflora, normalization in bowel movements, and reduction in loose stools as a result of antibiotic use.

The benefits of probiotics are broad and researchers are continually uncovering more positive outcomes associated with taking a probiotic. Like most over-the-counter products, however, probiotics do not come without any concern of side effects. Most side effects are negligible or mild, but a discussion of the possible effects is still warranted. More details on side effects can be found below.

What are the most common types of probiotic bacteria?

Probiotics are made up of different strains of good bacteria. Probiotics are not all created equal. It is important to take a high quality product that delivers the microorganisms that are necessary to maintain good health. In recent years, researchers have focused heavily on a few strains of microorganisms in probiotics.

Some probiotic supplements combine multiple strains to deliver more possible benefits. Other probiotic supplements may contain a single strain to target a specific health outcome. Your specific health condition or desired outcome will likely dictate which type of probiotic is best for you. It is important to speak with your physician to determine which type of probiotic is most appropriate for you.

What should I expect when I start taking probiotics?

Before taking a probiotic, you should speak with your physician about the best way to begin. If you may benefit from a probiotic, your physician may recommend starting with bacteria-containing foods before starting a probiotic supplement. For example, foods such as yogurt and kefir contain good bacteria. Your physician may recommend that you start with a smaller dose (lower CFUs) when first starting out. Some of the most common effects include stomach and bowel changes (e.g. irregular bowel movements) since the bacteria directly impact your digestive and metabolic systems.


Are there side effects to taking probiotics?

Like over-the-counter products, probiotics may have some negative side effects. Luckily, most people do not experience negative side effects. And those people that do experience side effects often only face mild symptoms. Overall, probiotics are normally considered to be safe because they contain strains of microbes that are already present within our bodies. Potential side effects of probiotics may include any of the following:

  • Digestive side effects such as gas or bloating
  • Headaches

Before beginning a probiotic, you should speak with your physician. He or she will be able to discuss the side effects that you may experience in greater detail and recommend a specific probiotic if a probiotic is right for you.

You're unique.
Your supplements should be too.

Take the quiz