Understanding the Side Effects of Olive Oil and Lemon Juice

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Drinking olive oil mixed with lemon juice is a popular wellness trend, often promoted as a liver “cleanse” or gallbladder “flush.” Both ingredients are healthy foods, but drinking them together in large amounts has real downsides, and some claims are myths. Here are the side effects, the evidence behind the benefits and a safer way to use them.

Quick answer: A tablespoon of olive oil with a squeeze of lemon is safe for most people. Large “flush” doses can cause diarrhea, nausea, heartburn and a big calorie load (about 120 kcal per tablespoon of oil). Gallbladder flushes are not proven to remove stones, and the “stones” people see afterwards are usually clumps formed from the oil itself.

Olive oil and fresh lemon on a kitchen table

Side Effects of Olive Oil and Lemon Juice

Side effectWhy it happensHow to avoid it
Diarrhea and crampsLarge amounts of oil on an empty stomach act as a laxativeKeep to 1 tablespoon; take with food
NauseaStraight oil is hard to stomach for many peopleMix into a dressing instead of drinking it
Heartburn / refluxLemon acidity and fat can relax the lower esophageal sphincterAvoid if you have GERD
Weight gainOlive oil has about 120 kcal per tablespoonCount it in your daily calories
Tooth enamel wearCitric acid erodes enamelRinse with water; do not brush for 30 minutes
Gallbladder painA large fat dose makes the gallbladder contract hard; risky if you have gallstonesSee a doctor instead of trying a flush

Nutrients in Olive Oil and Lemon Juice

Per serving1 tbsp extra-virgin olive oil1 tbsp lemon juice
EnergyAbout 120 kcalAbout 3–4 kcal
FatAbout 14 g (mostly monounsaturated)0 g
Vitamin EAbout 2 mg (about 13% DV)—
Vitamin C—About 6 mg
Source: USDA FoodData Central.
Nutrients in olive oil and lemon juice

Benefits: What Is Actually Supported

  • Heart health (olive oil): in the large PREDIMED trial, a Mediterranean diet supplemented with extra-virgin olive oil reduced major cardiovascular events compared with a lower-fat diet (Estruch et al., NEJM, 2018). The benefit came from using olive oil in meals over years, not from drinking shots.
  • Polyphenols: extra-virgin olive oil contains polyphenols with antioxidant and anti-inflammatory activity.
  • Vitamin C (lemon): a modest amount that also helps you absorb iron from plant foods.
  • Constipation: a small amount of oil can soften stools short term, but fiber, fluids and activity are better long-term fixes.

Myths vs Facts

MythFact
It detoxes the liverYour liver clears toxins on its own. No study shows olive oil and lemon “cleanse” it.
It flushes out gallstonesStudies of “flush” residue found the green lumps are soap-like stones formed from oil, lemon and digestive juices, not real gallstones.
It melts belly fatNo food targets belly fat. The oil adds calories.
It must be taken on an empty stomachThere is no evidence that timing matters; taking it with food is gentler.
Myths and facts about olive oil and lemon juice

Should You Drink Them Together?

If you enjoy it, a tablespoon of extra-virgin olive oil with a squeeze of lemon once a day is safe for most healthy adults. But you get the same benefits by using olive oil and lemon in food: a lemon-olive oil salad dressing, drizzled over vegetables or fish. Avoid large “cleanse” doses, and talk to your doctor first if you have gallstones, GERD, pancreatitis or take blood-thinning medication with high-dose supplements.

Simple lemon olive oil dressing

  • 3 tablespoons extra-virgin olive oil
  • 1 tablespoon fresh lemon juice
  • ½ teaspoon Dijon mustard, pinch of salt and pepper
  • Shake in a jar; keeps 1 week in the fridge.
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Frequently Asked Questions

What happens if you drink olive oil and lemon juice every morning?

A small amount (1 tablespoon oil) is generally well tolerated. You add about 120 calories. Larger amounts often cause loose stools or nausea.

Does olive oil and lemon juice help with gallstones?

No. There is no good evidence that it dissolves or removes gallstones, and a large fat dose can trigger painful gallbladder attacks. See a doctor.

Can olive oil and lemon help constipation?

It may give short-term relief for some people, but fiber, water and exercise are the proven long-term solutions.

Is it better to use extra-virgin olive oil?

Yes. Extra-virgin olive oil keeps more polyphenols than refined olive oil.

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