Picture of a young woman holding her hands out looking undecided
Picture of a young woman holding her hands out looking undecided

ellaOne® Side Effects

When choosing to take any medicine, it is perfectly understandable to be a little concerned about possible side effects. By making yourself aware of some of the potential side effects when taking ellaOne®, the most effective morning after pill*, you can feel confident in your choice of emergency contraception.

Sadly, because many people don’t learn about emergency contraception, there are lots of myths and misinformation about scary side effects that are often over-exaggerated or are totally incorrect. All medicines have potential side effects, and ellaOne® is no exception, but generally it is well tolerated. Most people will experience no side effects at all.

For more information about ellaOne®, check out: All you need to know about ellaOne®.

Deborah Evans, Pharamacist
ellaOne

What are the side effects of the morning after pill?

Side effects of ellaOne®

Pharmacist Deborah Evans** says, “like all medicines, the morning after pill can cause side effects, although not everyone gets them, and most people will not experience any side effects at all. Your pharmacist can help you to know what to do if you do.”

It is important to remember that ellaOne® is generally well tolerated, and many people experience no side effects when using this medicine. Everyone is different, so any side effects that do occur will vary from person to person.

These are some of the common* side effects of ellaOne®:
(*estimated to affect up to 1 in 10 people)

  • Headache

  • Stomach Pain

  • Breast tenderness

  • Changes in mood

  • Feeling sick or vomiting

If you vomit within three hours of taking ellaOne® you need to contact your pharmacist or another healthcare professional, as the medicine will no longer be effective and you will need to take another dose.

Less common side effects of ellaOne®

There are some uncommon side effects associated with taking ellaOne®. These side effects will affect up to one in one hundred people.

Uncommon side effects of ellaOne® are:

  • Diarrhoea and wind

  • Heartburn

  • Dry mouth

  • Irregular vaginal bleeding (i.e. between periods)

  • Heavy periods and prolonged PMS

  • Vaginal irritation or unusual discharge

  • Changes to your appetite and sex drive

  • Hot flushes

  • Anxiety or agitation

  • Trouble sleeping

  • Sleepiness

  • Migraine

  • Visual disturbances

  • Acne

  • Itchy skin

These side effects are uncommon (affecting up to 1 in 100 people), but if they do occur then they don’t typically last for very long.

Deborah advises to take caution if you experience any side effects that might affect your daily activities: “for instance, some people can experience mild to moderate dizziness, so take care if you have these symptoms if driving or using machines.”

What to do if you experience any side effects after taking ellaOne®?

The most common side effects associated with taking ellaOne® are mild and shouldn’t cause any concern.

If you experience any side effects that seem out of the ordinary, that aren’t listed in this article, or that worry you, you should also contact a pharmacist or healthcare professional.

Your period after taking ellaOne®

Most people will have their next period as usual after taking ellaOne®. Some people however might find that their period is either a few days early or late after taking ellaOne®.

Missing a period is one of the earliest signs of pregnancy, but if your period is less than seven days late after taking ellaOne® try not to panic, as this is not uncommon. If your period is more than a week late, or unusually light or heavy, you should take a pregnancy test or talk to your GP or pharmacist.

Some people may also experience irregular bleeding after taking ellaOne®. If you are unsure whether this bleeding is your period or not, you can take a pregnancy test 21 days after the unprotected sex took place to check whether you are pregnant or not.

How do I know ellaOne® has worked?

There is a lot riding on this small pill, and you’ll want to be reassured that it is working as intended. Unfortunately, there’s no way to know whether ellaOne® has worked until your next period arrives.

ellaOne® can make your next period late, so even if it is a few days later than usual, try not to panic, this is quite common. If your period is more than a week late, you may want to take a pregnancy test or talk to your GP or pharmacist.

Some side effects of ellaOne® have been likened to the early signs of pregnancy. Things like breast tenderness, stomach pain and nausea or vomiting can occur either as a side effect after using ellaOne®, or as a symptom of pregnancy.

Deborah’s advice is: “the only way to tell if the morning after pill has worked is to do a pregnancy test 3 weeks after the unprotected sex or if there are any concerns at all about pregnancy.”

Will ellaOne® affect my future fertility?

Young woman looking happily at her pregnancy test whilst on the phone
Young woman looking happily at her pregnancy test whilst on the phone

No. Unfortunately, thanks to a lot of myths and misinformation, this is a concern that many women have when considering emergency contraception. However, there is NO evidence that ellaOne® will have any affect on a person’s fertility.

Deborah Evans says “the morning-after-pill can be taken after any episode of unprotected sex or contraceptive failure without causing any effect on future fertility. Some women believe that they can only take it a few times before it impacts on being able to get pregnant in the future, but this is NOT true”

Fertility returns to normal rapidly after taking ellaOne®, which is why it is very important to practice safe sex after taking emergency contraception (and all the time – if you’re not trying to conceive).

Some people assume that taking ellaOne® means that they won’t be at risk of pregnancy if they have unprotected sex in the days or weeks afterwards. This isn’t true, and if you are using hormonal methods of contraception (like the pill), you should also use a condom until your next period, after taking ellaOne®.

How can I buy ellaOne®?

ellaOne® is available without prescription from most leading pharmacies. For more information on buying at a pharmacy, click here.

You can also order ellaOne® online, with options for same day and next day delivery.

Even with the best of intentions, accidents can happen, condoms can break, pills can be forgotten, and anyone might find themselves in need of the morning after pill. This doesn’t mean that you should feel panicked or ashamed, but that it’s time to take the responsible steps if you want to try to avoid an unplanned pregnancy.

Learning about the morning after pill and how it works is key to feeling confident about contraception. If you want to learn more about the ellaOne® morning after pill, you can find a whole treasure trove of information over at All you need to know about ellaOne®.

Have more questions to ask? Try our ellaOne® FAQs page, to see if they might have been answered there.

Photo of Samuelle Yohou
Samuelle Yohou
Associate Medical Manager
Medically reviewed in February 2020.

**Deborah Evans does not endorse any medicinal products or brands.