Abstract: The present invention relates to a method for sealing capsules to render them both tamper-proof and tamper-evident. The method comprises locating a quantity of an adhesion-promoting fluid between the adjacent surfaces of the overlapping capsule wall, and thereafter applying dielectric heat energy in the vicinity of the adhesion-promoting fluid, to cause the adjacent surfaces of the capsule walls to form a permanent bond. Preferably, the adhesion-promoting fluid may comprise a non-solvent for the capsule walls that further has a high dielectric constant. Suitable adhesion-promoting fluids include lower alkanols. The method is capble of rapid operation and is inexpensive by virtue of its simplicity. Reliable capsule seals are achieved that are incapable of violation.