Our dog has had issues with bilous vomiting over the years where we've come home to bright green/yellow stains of bile on the carpet.
Spot shot works really well - if you have new carpet that was already pretreated with ScotchGuard, you should be in good shape.
If not, what we've found works best (with 2 pets and 2 kids, we have lots of stains) is:
clean as you are, then take a clean (white preferably) towel, fold it several times to get many layers (or use multiple towels) to absorb the liquid in the carpet.
Put a heavy object on top such as a trunk, heavy box, etc.
Keep the object there for ~24 hours and avoid the temptation to peek to see if it's working.
The weight of the object will act like a wick and will pull both the liquid and the stain out of the carpet.
We've used it MANY, MANY, MANY times, and we're yet to have a stain we can't get out this way.
Good luck!