What kind of coolant should I use in my 2000 Honda Accord?

I'm not sure what kind of coolant is in the car at the moment. It's green. Everything I've seen online says to use the Prestone 50/50 (yellow). Will it hurt to mix the two?

It should be O.K. To mix them.

If the coolant is low enough to need refill, it is time for a cooling system service, including refill with the correct coolant, preferably from Honda. Honda's prices are reasonable and the cost of using the wrong coolant can be high. In my more naïve years I used conventional green in my daughter's 1993 Accord and the water pump seal gave out 20K miles before the timing belt change was due. There are more than a dozen different coolant chemistries (Ford alone uses 4 or 5 different chemistries) and there's always a price in reliability when using the wrong one.

Prestone 50/50 is green… The traditional ethyl based coolant is a yellow green. Oh and cars do not have inert feelings.

The green antifreeze is fine.