They all consumed products including sausages, steaks and meatballs which were raw when purchased and cooked at home.
The venison is believed to have been bought from various shopping outlets.
Health and food standards officials, headed by Health Protection Scotland (HPS), are investigating.
Dr Syed Ahmed, consultant with Health Protection Scotland, said "It is important that all deer meat should be cooked thoroughly and should not be eaten medium or rare.
"The risk of E. coli O157 infection can be reduced by careful hand-washing, especially after contact with animals, handling raw meats, after going to the toilet and immediately before preparing or eating food and by making sure that food is always properly prepared."
Nine people across Scotland have contracted the same strain of E. coli O157 after eating venison.