Motrin’s active ingredient is ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID). The standard adult tablet, Motrin IB, contains 200 mg of ibuprofen per caplet. Beyond that core ingredient, the specific formulation you’re looking at changes what else is in the bottle, since Motrin comes in several versions for adults, children, infants, nighttime use, and combination pain relief.
Standard Motrin IB (Adult Tablets)
Each film-coated caplet delivers 200 mg of ibuprofen. This is the same dose you’ll find in store-brand ibuprofen and in Advil. Prescription-strength Motrin tablets come in higher doses of 400 mg, 600 mg, and 800 mg, but those require a doctor’s prescription and aren’t the same product you’d pick up off the shelf.
The inactive ingredients in adult Motrin IB are the standard mix of binders, coatings, and stabilizers that hold the tablet together and help it dissolve properly in your stomach. These include things like starch, wax coatings, and coloring agents. If you have known sensitivities to dyes or fillers, check the specific package, since inactive ingredient lists can vary slightly between tablet and caplet forms.
How Ibuprofen Works in Your Body
Ibuprofen blocks enzymes called COX-1 and COX-2 that your body uses to produce prostaglandins. Prostaglandins are chemicals that trigger inflammation, pain, and fever. By blocking their production, ibuprofen reduces all three at once. It binds to these enzymes quickly and reversibly, which is why its effects wear off after several hours and you need another dose.
This mechanism is what makes ibuprofen effective for headaches, menstrual cramps, muscle aches, arthritis pain, and mild fevers. It’s also why ibuprofen can irritate your stomach lining: prostaglandins play a protective role there, and blocking them removes some of that protection.
Children’s Motrin (Liquid Suspension)
The children’s liquid version contains 100 mg of ibuprofen per 5 mL (one teaspoon). The inactive ingredient list is longer than the adult tablet because the liquid needs sweeteners, thickeners, and flavoring to make it palatable for kids. It includes sucrose and acesulfame potassium as sweeteners, xanthan gum and pregelatinized starch as thickeners, glycerin, polysorbate 80, sodium benzoate as a preservative, citric acid, purified water, and artificial flavors.
It also contains two dyes: D&C Yellow No. 10 and FD&C Red No. 40. If your child has a known sensitivity to artificial food dyes, this is worth noting. The berry or grape flavoring varies by product, but Red No. 40 appears across most versions.
Infants’ Motrin (Concentrated Drops)
The infant drops are more concentrated: 50 mg of ibuprofen per 1.25 mL. This smaller volume makes dosing easier with the included syringe. The inactive ingredients overlap heavily with the children’s version but aren’t identical. They include citric acid, caramel coloring, FD&C Red No. 40, flavors, glycerin, polysorbate 80, pregelatinized starch, purified water, sodium benzoate, sorbitol solution, sucrose, and xanthan gum. The infant formula uses sorbitol and caramel that the children’s version does not, while skipping the Yellow No. 10 dye.
Motrin PM (Nighttime Formula)
Motrin PM contains two active ingredients. Each caplet has 200 mg of ibuprofen for pain relief plus 38 mg of diphenhydramine citrate, which is an antihistamine that causes drowsiness. Diphenhydramine is the same sleep-inducing ingredient found in Benadryl and most over-the-counter sleep aids. The combination is designed specifically for people whose pain is keeping them awake. If you don’t need the sleep aid component, standard Motrin IB is the better choice.
Motrin Dual Action With Tylenol
This newer formulation combines two different pain relievers in a single tablet: 125 mg of ibuprofen and 250 mg of acetaminophen (the active ingredient in Tylenol). The two drugs work through completely different mechanisms. Ibuprofen reduces inflammation at the source of pain, while acetaminophen acts primarily in the brain to change how you perceive pain. Combining them at lower individual doses can provide relief comparable to higher doses of either drug alone.
If you’re taking Motrin Dual Action, you should not take additional Tylenol or additional ibuprofen products at the same time, since both are already in each tablet.
Allergy Risks From Motrin’s Ingredients
The most significant allergy concern is ibuprofen itself. People who are allergic to aspirin face a higher risk of reacting to ibuprofen because both drugs target the same enzyme pathway. Reactions can include hives, facial swelling, skin reddening, rash, blisters, wheezing, and in rare cases, shock. Anyone who has ever had an allergic reaction to any NSAID pain reliever should avoid all Motrin products.
For the liquid children’s and infant formulations, the artificial dyes and sodium benzoate preservative are the inactive ingredients most likely to cause sensitivities. These reactions are far less common than ibuprofen allergies but do occur, particularly in children with existing dye sensitivities. The exact inactive ingredient list is printed on every Motrin package and is also available on the DailyMed database maintained by the National Library of Medicine.