How to Recognize Changes in Color, Odor, or Texture in Expired Drugs

When a pill turns yellow, a cream separates into layers, or a liquid smells odd, it’s not just old - it could be dangerous. Expired medications don’t just lose effectiveness; they can physically break down in ways that make them unsafe to use. You don’t need a lab to spot these changes. With a little training and attention, you can tell if a drug has degraded just by looking, smelling, or touching it. This isn’t about guessing. It’s about recognizing clear, documented signs that science has proven can signal harm.

What Changes to Look For

Expired drugs change in three main ways: color, odor, and texture. These aren’t random. They follow patterns seen in thousands of tested samples. The most common sign? Discoloration. According to NASA’s 5-year study of medications under stress, 68.3% of expired solid drugs showed visible color shifts. Tetracycline antibiotics turn from white to yellow or brown. Nitroglycerin tablets and liquids go from clear to yellow-brown. Even common painkillers like aspirin can develop brown spots around the edges. These aren’t stains - they’re chemical reactions. Oxidation, moisture exposure, or heat break down the active ingredients and create new compounds.

Odor changes are harder to ignore. If a medication smells rancid, sour, or like wet cardboard, it’s not just stale. Moisture has gotten in. This is especially common with capsules made from hygroscopic drugs like amoxicillin. These pills absorb water from the air, causing the powder inside to clump, ferment, or grow mold. You might smell something like old cheese or vinegar. That’s not normal. It’s a red flag.

Texture is where things get tricky. Tablets should be hard and smooth. If they’re crumbly, chalky, or sticky, the binder has broken down. Capsules may feel softer than usual or leak powder when squeezed. Creams and ointments should be uniform. If you see oil floating on top or water pooling at the bottom - that’s phase separation. It means the emulsion failed. Liquids should be clear. If you see floating particles, cloudiness, or sediment, that’s particulate formation. The FDA’s USP <788> standard says sterile liquids must have fewer than 6,000 particles larger than 10 microns per container. You can’t count them, but you can see them.

How Different Medications Degrade

Not all drugs degrade the same way. The form matters.

• Tablets: Discoloration happens in 73.5% of expired cases. Pills with iron or tetracycline are especially prone. If the color isn’t uniform - darker in the center or around the edges - it’s likely degraded.
• Capsules: 41.2% show caking or clumping. This is common with antibiotics and antihistamines. If the powder inside sticks together like wet sand, moisture has ruined the formulation.
• Creams and ointments: Phase separation occurs in 38.6% of expired samples. Clotrimazole cream or mupirocin ointment might look like two layers. One part is oily, the other watery. That’s not normal separation - it’s failure.
• Liquids: 52.4% develop particles or cloudiness. Insulin, eye drops, and antibiotics are common examples. If you shake it and the cloud doesn’t clear, don’t use it.

Some drugs are more sensitive than others. Light-sensitive medications like nitroglycerin or riboflavin degrade fast if stored in clear bottles. Heat accelerates breakdown. A study showed that every 10°C rise above 25°C speeds up degradation by 2.3 times. If your medicine sat in a hot car, on a windowsill, or in a bathroom cabinet, it’s more likely to be bad - even if it’s not expired yet.

What You Can Do Without Tools

You don’t need a microscope or spectrometer to spot trouble. Start with these steps:

1. Use good light. Natural daylight is best. If you’re indoors, use a 500-lux lamp. Avoid dim or yellow lighting - it hides color changes.
2. Place it on a white surface. A clean white paper or plate helps you see subtle shifts. A yellow pill on a yellow towel? You’ll miss it.
3. Smell it. Don’t just sniff the cap. Open it and smell the contents. A new pill shouldn’t smell like anything. If it does, something’s wrong.
4. Touch it. Gently press a tablet. If it crumbles or feels soft, it’s degraded. For creams, rub a small amount between your fingers. If it feels grainy, greasy, or separates, toss it.
5. Compare. Keep a reference. Take a photo of a new, unopened bottle. Later, compare. Even small differences matter.

The University of Wisconsin’s RARC team uses colored dot stickers on expiration dates - red for 2025, blue for 2026 - so staff can spot old meds fast. They also train staff to write detailed notes: not just “discolored,” but “light brown discoloration concentrated at tablet edges.” Specifics save lives.

What You Can’t Trust

Not every change means danger - and not every danger shows up visibly.

Some drugs naturally change color. Some antibiotics turn yellow as they age - that’s normal. But if the color is darker than usual, or uneven, that’s not normal. The same goes for texture. Some creams are thick. Some liquids are cloudy. Always check the manufacturer’s reference. The FDA’s Drug Expiration Database has images of what’s normal vs. what’s degraded.

Worse, some drugs degrade without any visible signs. A 2017 study by the National Institute of Justice found that 34.8% of tablets with below-acceptable potency showed no color, odor, or texture changes. That’s why physical checks alone aren’t enough. They’re a first line of defense - not the final word. If you suspect a drug is bad, even if it looks fine, don’t take it. Get a new one.

Why This Matters

The World Health Organization estimates that 10.5% of expired medications show physical changes that affect safety. In hospitals, 37.6% of expired drug incidents involved overlooked discoloration. One FDA report documented a hospital that kept using morphine sulfate with fine crystals - thinking it was normal. Fourteen patients had adverse reactions.

It’s not just about potency. Degraded drugs can cause allergic reactions, organ damage, or infections. A contaminated liquid can introduce bacteria. A separated cream can deliver uneven doses. A degraded antibiotic might not kill the infection - and could make resistant strains worse.

That’s why the pharmaceutical industry spends $3.2 billion a year on stability testing. It’s not just regulation. It’s survival. And while labs use high-tech tools like FTIR spectroscopy and Raman spectrometers, the basics still work. If you can see, smell, and feel the difference, you can prevent harm.

What to Do When You Spot a Problem

If you notice any of these changes:

• Stop using the medication immediately.
• Do not flush it down the toilet or throw it in the trash. Many pharmacies have take-back programs.
• Bring it to your pharmacist. They can confirm if it’s degraded and replace it.
• If you’ve already taken it and feel unwell, contact a healthcare provider or poison control center.

Don’t assume it’s safe because it’s “just a little expired.” Expiration dates aren’t arbitrary. They’re based on real data from stability testing under controlled conditions. If a drug was stored poorly - in heat, humidity, or sunlight - it could be unsafe long before the date on the label.

How to Prevent This

Prevention starts with storage.

• Keep medicines in a cool, dry place - not the bathroom or near the stove.
• Use original containers. They’re designed to block light and moisture.
• Don’t transfer pills to pill organizers unless you use them within a week.
• Check expiration dates every three months. Mark them on your calendar.
• When in doubt, throw it out. A new prescription costs less than a hospital visit.

Pharmacies and hospitals now use digital systems like Artragen’s ColorTrack to measure color changes to within ±0.5 CIELAB units. But for most people, the human eye is still the best tool - if you know what to look for.