Amber is a unique embalming agent, so inclusions in amber attract considerable attention. The largest proportion of the inclusions - 80% - are insects. The aromatic resin attracted the tiny inhabitants of the "amber forest" and preserved them through the centuries, trapped in its shining embrace as evidence of the insect fauna of the time. Spiders are also common among the inclusions, and there are unique finds such as an amber-encased lizard and a frog. Forgeries of inclusions in amber are also sold. The inclusions help to date the amber.

Plant remains are often found as inclusions in amber. These are much more difficult to identify. They are used to reconstruct the landscape of the "amber forest". For example, swamp cypress remains occur in amber from both Europe and America. This suggests that the resin of the swamp cypress could also have changed into amber.

Mineral matter and soil also occurs as inclusions.