Two-component packages for storing two components which are to be isolated from each other during storage and mixed when the package is opened. The packages comprise an outer container (2) for a first component having a threaded neck (3). A closure cap (5) is provided to close the threaded neck (3). A capsule (6) for a second component is located inside the outer container (2) and extends into the threaded neck (3) of the outer container (2). A first ratchet means extends downwardly from the base of the closure cap (5) and engages with a second ratchet means on the top part (7) of the capsule (6), whereby the closure cap (5) can be screwed down without rotating the said top part (7) of the capsule (6), but cannot readily be unscrewed without also rotating the said top part (7). A rotation block (13,14) prevents rotation of a lower part (11) of the capsule (6). As a result, unscrewing the closure cap (5) exerts a torsional force on the capsule (6). Release means (12), such as a screw thread, are provided in the capsule (6) to release the contents of the capsule (6) when the said torsional force is applied.