Both prescription and over-the-counter medicines are required by law to be safe and correctly labeled. Despite the regulations, however, the consumer is the final line of defense, and should never take safety and product purity for granted.

Case in point: New Yorker Christie Judson recently encountered a suspicious bottle of SmartBurn, an over-the-counter weight-loss product.

"I brought the bottle home," said Judson. "The box had not been squished or opened or anything. I just opened up the cardboard, took the bottle out, uncapped it, and the seal was broken."

She found a surprise beneath the broken seal.

"The real SmartBurn (pills) are white. And they're just so long and fat," she said. "These ones are round white ones, and oblong orange ones."

Judson called the SmartBurn company and Wal-Mart and was told to bring that package back. She also called NewsChannel 4.

"I called you because it's just not enough taking them back and getting a refund," said Judson. "It could happen to somebody else. You don't know what's in there."

To its credit, Wal-Mart immediately pulled the merchandise and launched an investigation. They found what NewsChannel 4 found in bottles we spot-checked: The other SmartBurn packages showed no sign of tampering and contained no mixed or altered tablets and capsules.

Preliminary results of the contents of the bottle Judson found indicate aspirin and multivitamins were inside. Though it believes the case is isolated, Wal-Mart said it take these matters seriously and will continue the investigation.

When buying any medicines from any store, be careful about:

Breaks, cracks, or holes in the outer or inner wrapping.

A shrink band that appears distorted or stretched; it could have been rolled down.

The container consistency if it appears to be too full or not full enough.

Bits of paper or glue stuck on the rim of the container.

A cotton plug or filler that is torn, sticky, or stained.

Most products that have tamper-resistant packaging say so on the box. Following each step in opening it can help you detect tampering. Also, don't forget to look at the bottom of the bottle.