Shocked residents received graphic images through their letterbox from an anti-abortion campaigner.
Several houses in Pretoria Road, Halstead, had brown envelopes containing pictures of aborted foetuses posted through their door on Wednesday.
Police officers attempted to collect the potentially upsetting images before residents had the chance to open the envelopes.
Resident David Coulthread said: “My wife came home at about 6.20pm and a police officer was there and said if we’d had a brown envelope through the door we might not want to open it.
“It had a picture of what appears to be an aborted foetus.
“If it is an anti-abortion campaign, it is fair enough to hold an opinion, but it was so extreme and graphic."
An Essex Police spokesman said: “Police were contacted just before 4.30pm with reports a resident in Pretoria Road, Halstead, had an envelope posted through their letterbox which contained pictures of foetuses and information pertaining to be anti-abortion.
“Police visited other houses in the road, offered reassurance and removed any unwanted envelopes.
“Anyone with information is asked to call police on 101.”