There are 7 words that start with 'hemag'.
| hemagog | hemagogs | 
| hemagglutinin | hemagglutinate | 
| hemagglutinins | hemagglutinated | 
| hemagglutinates | |
Note: These 7 words that start with 'hemag' are found from the USA & Canada version of the tournament Scrabble word list.