Castor oil is a thick, versatile oil used for everything from relieving constipation to moisturizing skin and conditioning hair. How you use it depends entirely on what you’re using it for, and each application has its own method, frequency, and precautions worth knowing. Here’s a practical breakdown of the most common uses.
For Constipation Relief
Castor oil is an FDA-recognized stimulant laxative. The active component, ricinoleic acid, triggers contractions in the intestinal wall that help move things along. It works fast, typically within two to six hours.
The standard dose for adults and children over 12 is 1 to 4 tablespoons (15 to 60 mL) taken in a single dose. Children ages 2 to 11 take a much smaller amount: 1 to 3 teaspoons (5 to 15 mL). It should not be given to children under 2. Castor oil tastes unpleasant on its own, so mixing it into a glass of juice or chilling it beforehand can make it easier to get down. Take it on an empty stomach for fastest results, and plan to stay near a bathroom.
This is a short-term remedy only. Using it regularly can lead to dependence, where your bowels stop functioning normally without it.
For Your Scalp and Hair
Castor oil is popular as a deep-conditioning scalp treatment. It’s extremely thick (much more viscous than coconut or olive oil), so a little goes a long way. Apply it no more than once a week to avoid buildup that can leave hair looking greasy or weigh it down.
To apply, scoop a small amount onto your fingertips and massage it directly into your scalp using circular motions. If you want to condition the lengths of your hair as well, work a thin layer from mid-shaft to ends. Leave it on for at least 30 minutes, or overnight if you wrap your hair in a towel or shower cap to protect your pillowcase. Because of its thickness, castor oil can be difficult to wash out. A clarifying shampoo is the most effective option. Lather, rinse with warm water, and repeat if your hair still feels oily. Alternatively, mix one tablespoon of baking soda into a cup of water, apply it to your hair, let it sit for 15 minutes, and rinse. An apple cider vinegar rinse (same ratio: one tablespoon to one cup of water) also helps dissolve residual oil. Use a wide-toothed comb after washing to detangle and remove any remaining traces.
You’ll see claims that castor oil promotes hair growth. There’s no strong clinical evidence for this, but the moisturizing effect can reduce breakage and make hair appear fuller over time.
For Your Face and Body
Ricinoleic acid has moisturizing properties that support the skin’s barrier function. Castor oil acts as an occlusive, meaning it forms a protective layer on the surface that locks in moisture rather than adding water itself. This can make skin appear smoother and more hydrated, particularly in dry or cold conditions.
For facial use, apply a few drops to clean, slightly damp skin at night. Mixing it with a lighter carrier oil (like jojoba or sweet almond oil) makes it easier to spread and less likely to clog pores. If you’re prone to acne, this dilution step is important. Castor oil is thick enough to block pores when used undiluted, which can trigger breakouts on already congestion-prone skin.
Before putting castor oil on your face for the first time, do a patch test. Apply a small amount to the inside of your arm or the bend of your elbow and repeat twice a day for seven to ten days. If you see redness, itching, or irritation during that window, skip it.
For dry patches on the body (elbows, heels, knees), you can apply it more generously. Rub it in after a shower while skin is still damp, then let it absorb for a few minutes before getting dressed.
For Eyelashes and Eyebrows
Many people apply castor oil to their lashes and brows hoping to encourage thicker growth. The method is straightforward: dip a clean spoolie brush or cotton swab into a small amount of oil and coat the lashes or brow hairs before bed. Wipe away any excess so it doesn’t migrate into your eyes overnight.
A word of caution here. The American Academy of Ophthalmology has noted that store-bought castor oil is not formulated for use near the eyes. These products may contain dyes, preservatives, fragrances, or other additives that can cause irritation or infection, and they are not sterilized. If oil does get into your eyes and causes redness, burning, or blurred vision, rinse thoroughly with clean water. Claims that castor oil can treat cataracts or glaucoma are false. As ophthalmologist Vicki Chan has pointed out, those conditions occur inside the eyeball, so a topical oil applied to the surface cannot reach or fix them.
Castor Oil Packs for Soreness
Castor oil packs are a traditional remedy for joint stiffness and general soreness. The idea is to hold warm, oil-soaked cloth against the skin for an extended period to allow deeper absorption.
To make one, cut unbleached cotton or wool flannel into rectangles roughly 12 by 10 inches. You’ll need at least three or four layers. Pour castor oil into a bowl and submerge each piece of cloth until it’s fully soaked. Using tongs (the oil is messy), lay the first soaked cloth flat on a piece of plastic sheeting, like a cut-open garbage bag. Stack the remaining soaked cloths on top. Place the pack directly on the area you want to treat, oil side against skin, and leave it on for 45 minutes to an hour. Some people place a hot water bottle or heating pad over the pack for additional warmth, which can feel soothing on stiff joints.
The pack will be oily, so protect your furniture and clothing with old towels. You can reuse the same cloths several times by storing them in a sealed container in the refrigerator between sessions. When they start to look discolored or smell off, make a fresh set.
Uses to Avoid
Castor oil has a persistent reputation as a way to induce labor. Because it’s a laxative, it does cause uterine irritation and contractions, but these are a side effect of gastrointestinal distress, not true labor. Randomized studies have found that women who ingested castor oil were no more likely to go into labor than women who took nothing. The result is typically diarrhea and cramping with no meaningful progress toward delivery. UT Southwestern Medical Center notes the practice has largely fallen out of favor given the significant side effects and its inability to trigger real labor.
Avoid getting castor oil in your eyes intentionally, regardless of social media trends suggesting it helps with dryness or vision. And never take it orally in doses beyond the laxative range, as large amounts can cause severe dehydration from fluid loss.
Choosing and Storing Castor Oil
For skin and hair use, look for cold-pressed, hexane-free castor oil. Cold pressing extracts the oil without chemical solvents, preserving more of its natural properties. Jamaican black castor oil, which is made from roasted castor beans, has a darker color and slightly different texture that some people prefer for hair treatments. Both work similarly.
Store castor oil in a cool, dark place. It has a long shelf life (typically one to two years unopened), but exposure to heat and light can cause it to go rancid faster. If it develops an off smell or changes color significantly, replace it.