Cannabis Science

Does Weed Affect Plan B?

woman taking plan b

Taking a Plan B pill can be nerve-wracking. You’re probably wondering if you’ve taken it too late or may be concerned about the side effects. However, what many people don’t think about are the interactions between Plan B and other medications. If you’re a cannabis enthusiast, you’ll probably wonder, “Does weed affect Plan B?” Here’s what we know. 

Photo: Unsplash

Can You Smoke Weed After Taking Plan B?

Unfortunately, there is not a lot of information or research out there on whether or not you can smoke weed after taking Plan B. 

There is currently no evidence that weed can affect the effectiveness of Plan B.

“Cannabis interacts with some other medications, but there isn’t evidence to suggest it negatively or positively affects Plan B effectiveness, at least in rats.” according to Ila Dayananda Chief Medical Officer, OB-GYN at Oula Health.

However, even if weed doesn’t affect the effectiveness of Plan B, it doesn’t mean there are no risks involved. 

Dayananda tells us, “The simultaneous use of weed and Plan B may pose risks or side effects, although comprehensive studies on this specific combination are pretty limited. Both substances each have their respective effects on the body, and their interaction could lead to increased side effects such as dizziness, nausea, or mood changes.”

WebMD also says that smoking weed and taking Plan B can make you dizzy. 

If you are concerned about mixing weed and plan B, Dayananada suggests consulting with your doctor for more accurate advice. 

Can You Smoke Cigarettes After Taking Plan B?

If you’re a cigarette smoker, you may be wondering whether or not it’s safe to use Plan B.

Gateway Express Testing says if you are a smoker with certain conditions such as diabetes, blood clots in the legs or lungs, severe migraine headaches, heart disease, and other conditions, avoid taking Plan B. 

While they didn’t get into why, it’s likely that Plan B could exacerbate these conditions.

For example, hormonal birth control is known to increase your risk of blood clots. Therefore, if you’re prone to blood clots already, hormonal birth control may be risky, and you should definitely speak to your doctor before taking it.

However, Ro says that being a cigarette smoker does not bar you from using Plan B.

“Non-hormonal birth control options (the copper IUD, barrier methods) and progestin-only contraceptives (the minipill, the hormonal IUD, the shot) won’t interact with smoking cigarettes. The same goes for emergency contraception (like Plan B).”

Regular hormonal birth control methods, on the other hand, could interact negatively with cigarettes. 

Medical News Today says, “The combination of smoking and hormonal birth control may increase the risk of cardiovascular conditions, including high blood pressure, blood clots, and stroke.”

As a matter of fact, the Mayo Clinic says that smoking cigarettes while using hormonal contraceptives could increase the risk of severe effects. The more you smoke, the greater the risk.

“The risk increases with age and with heavy smoking (15 or more cigarettes per day) and is quite marked in women over 35 years of age.”

Can You Drink Alcohol After Taking Plan B?

Yes, you can!

There is no evidence that drinking alcohol will cause serious side effects or affect the effectiveness of a Plan B pill.

However, this is not the time to go binge drinking.

According to Nurx, “If you are drinking after taking the morning after pill, it’s best to drink in moderation. If you drink until you feel sick, you could throw up the pill before your body absorbs it.”

Alcohol does not seem to affect regular hormonal birth control either.

Addiction Center of America says that alcohol doesn’t seem to affect the effectiveness of birth control. 

However, they’re concerned that alcohol may alter your behavior and make you forget to take it regularly. Therefore, keep that in mind if you drink.

What Happens if You Smoke While on Birth Control?

You’re probably wondering if weed and your regular birth control may interact. We’re still not sure if weed affects the effectiveness of birth control. There are no studies that have concluded that.

Let’s look at the existing research on the effects of weed and birth control. 

Medical News Today says that if you’re an avid user of CBD, you may want to opt for progesterone-only birth control.

“As a result of these potential liver impacts, limited evidence indicates that CBD may affect some estrogen-based birth control methods but not progesterone-based birth control.”

In terms of side effects, using birth control and weed could worsen side effects such as dizziness.

Healthline says, “This means that using cannabis and birth control could heighten the effects of the cannabis — good and bad — like euphoria, sedation, anxiety, and slowed reaction time. THC may hang around in your body longer and produce more severe effects.

In addition, weed and birth control together may negatively affect your heart health. That’s because weed may increase your blood pressure and your heart rate, according to Healthline. 

On the other hand, a recent animal study investigated the behavior of female rats after exposure to both cannabinoids and hormonal contraceptives. The study concludes that weed, in low rewarding doses, does not significantly alter the motor and cognitive skills of female rats. Weed also doesn’t induce anxiety or depressive-like states in female rats either. 

Finally, there’s no evidence using a non-hormonal birth control method could interact with cannabis, whether negatively or positively. 


Does weed affect Plan B? We don’t have any evidence that smoking or using cannabis in any form can affect the effectiveness of Plan B. Medical professionals believe that using both together could exacerbate certain side effects, such as dizziness or nausea. Much more research is needed in this area. In terms of alcohol and cigarettes, generally speaking, it’s fine to use them after Plan B. However, it’s best to speak with your doctor, especially if you have pre-existing conditions.  


About Trevann

Trevann is Stoner Rotation’s Jamaica-based lead writer for the Science section of our cannabis blog. She graduated with honors receiving her Bachelor of Science degree in Molecular Biology from the University of West Indies, Mona. For the last three years, she has covered some of the biggest questions around cannabis and health underpinned with research from supporting studies, medical journals and scholarly articles. Got something on your mind? You can reach her at [email protected].