Abstract: A reliable and low cost indicator to be associated with a receptacle filled with dosage forms (e.g. over-the-counter drugs) and a corresponding method by which to quickly and easily warn a consumer that an unauthorized tampering may have occurred to the receptacle and the contents thereof. The tampering indicator is preferably either attached to or integrally formed with a seal at the underside of a removable receptacle cap. The tampering indicator comprises a fluid filled reservoir, a tab having a chemically treated indicator strip thereat, and a fluid path by which fluid from the reservoir communicates with the indicator strip. The indicator is engaged by the rim of the receptacle when the cap is positioned thereover by the dosage form manufacturer. Accordingly, fluid is forced from the reservoir into the fluid path. However, the fluid path is initially blocked at the engagement thereof by the receptacle rim.