What’s the worst thing that can happen if you take a medication that is past its expiration date? The medicine will just be a little bit weak, right? Wrong. Although that’s true in most cases, some outdated medications can become toxic and actually make you sick.

Knowing how to store medications, as well as when and where to dispose of them safely, is just as important as knowing how and when to take your medications. Follow these tips and you’ll be on the right track.

When your pharmacist sends you home with a new medication, keep it in its original container, which has your name and dosing information on it. Be sure to re-lock bottles with child-resistant packaging. Many medications—especially those harmful to children—are put in foil packaging. If you find these difficult to open, talk with your pharmacist. For each medication, the law provides for one type of package without child-resistant features. If you don’t have children in your home, these might work best for you (although consider whether young children ever visit your home). But whatever you do, don’t transfer your medications into an empty bottle. Someone else may take them, not knowing they belong to you. It’s been known to happen.

If you’re unsure, ask your pharmacist about the best place to store your medications. To keep children and pets safe, store medications in a high, locked cabinet. If that’s not possible, find a place that’s difficult for children to see and reach. Remember: A young child has no idea that these colorful objects are not candy. And even over-the-counter medications and vitamins—particularly those containing iron—can be dangerous, especially if taken in large amounts by children.

To keep a medication safe and potent, keep it out of direct sunlight in a cool, dry place. Some medications are affected by humidity, so the bathroom medicine cabinet isn’t always best. Other medications require refrigeration, but don’t keep medications there unless instructed to do so by your doctor or pharmacist.

It may be wise to keep a reserve supply of medications, in the event of an emergency. For example, if you need medications for a chronic condition, such as diabetes, asthma, HIV, or a psychiatric condition, carry at least a three to five day supply with you in a purse or briefcase in labeled containers. Make sure these are in child-resistant containers and that your purse or briefcase is kept out of the reach of children.

As for medication disposal, make it a part of your spring (and fall) cleaning ritual. Check expiration dates, but even if the medication is not dated, think of it as expired at six months after purchase. Also, dispose of a medication if it has changed colors or developed an unusual order—even if it’s not past its expiration date. Don’t put medications or vitamins into open trash containers or down the toilet. Instead, take all expired medications to your pharmacist for proper disposal. This is the best way to protect family pets, children, people who might scrounge through your trash—and the environment.

Medications are expensive, so it may be tempting to use them, even when they’ve expired. If this is your thinking, just remember the greater potential cost to you: your health and safety.