Abstract: A desiccant cap for a container and method of production the cap are disclosed. The cap is made to provide long term hermetic sealing to content kept in the container by providing hermetically sealed layer on the opening of the container that is to be removed only before first use of the content of the container. The cap further comprise case with a desiccant material that is adapted to keep the moisture in the container after first use under a defined level by drying moist air accessing the desiccant material through passages made in a porous sealing layer. This way the desiccant cap provides hermetic sealing until first use and on-going drying of moisture inside the container after first use, and keeps the desiccant material protected from moisture ambient until first opening.