An injection device comprises a housing 10 1 to 10 4 containing a syringe 24. The contents of the syringe 24 are viewable through a window 14 in the midsection 10 2 of the housing. The window 14 is concealed by a slideable shutter 12. The slideable shutter 12 is biased by a bias spring 22 which also biases an internal syringe carrier. Also disclosed is a reversible needle cap which operates initially to cap the front end of the housing and, upon removal thereof, pulls a needle sheath 30 off the syringe needle 26. The cap is designed to be reversible so that, after use, it can be reversed and reconnected to the housing to cover the exposed needle.
