Many people store their medications in the bathroom. But this popular spot is actually one of the worst places to keep medicine. Bathroom cabinets tend to be warm and humid, an environment that speeds up a drug's break down process.

This is especially true for tablets and capsules. Unnecessary exposure to heat and moisture can cause them to lose their potency prior to their labeled expiration date. For example, a warm, muggy environment can cause aspirin tablets to break down into acetic acid (vinegar) and salicylic acid, both of which are potential stomach irritants.

Instead, keep medicines in a cool, dry place and out of a child's reach.

If you must keep them in the bathroom, always keep the containers tightly closed. Never repackage them.

If medicines are to be stored in a kitchen, store them away from the stove, sink, and any heat-releasing appliances.

In rare cases, medicine that is improperly stored can actually become toxic. To prevent danger, follow these tips:

• Always store drugs out of the reach of children.
• Don't leave the cotton plug in a medication bottle. Doing so can draw moisture into the container.
• Check the expiration date each time you take a drug. Throw out and replace any medications that are out of date.
• Never use a medication that has changed color, consistency, or odor, regardless of the expiration date. Throw away capsules or tablets that stick together, are harder or softer than normal, or cracked or chipped.
• Ask your pharmacist about any specific storage instructions.

Travelers need to follow additional tips for safe storage of their medications:

• Before leaving home, list all your medications, as well as the name and number of your pharmacist and doctor.
• Pack your medicine in a carry-on bag instead of a checked suitcase.
• Bring an extra supply with you in case your return is delayed.
• Never leave medicines in an automobile, where heat can rapidly destroy the drug.
• Watch time changes. Set a separate watch to your usual time so you can remember when to take any medication.

More information on travel tips and safe storage of medicines is available through the American Society of Health Systems Pharmacists at www.safemedication.com.

Crichton B. Keep in a cool place: exposure of medicines to high temperatures in general practice during a British heatwave. J R Soc Med. 2004;97:328–329.

Karch AM. When it's time to clean out the medicine cabinet. Am J Nurs. 2002; 102(2): 23.