Today’s entry is often more of a spelling issue than a grammar issue. But a mistake in this regard can be pretty amusing.
A regimen is a systematic plan or regular course of action to achieve a specific goal. Usually we’re talking about eating healthy food, exercising with a certain regularity, or following a plan for taking certain medicines when we use the word. For example,
I follow a daily regimen of exercise and physical therapy to maintain my strength as an athlete.
My condition means I have to follow a particular regimen of this over-priced drug.
A regiment, on the other hand, is a military unit usually made of several large groups of soldiers.
Example: Before the battle, the regiment staked out a strong position behind the hill.
So if you follow a daily regiment, you might get shot in the process.