Can i take alka seltzer original before going to bed?

Maybe. Looking at the ingredients it has aspirin, a NSAID known to cause stomach irritation/erosions and some antacids. Many find the preparation helpful but as an over-the-counter product it is not monitored by the FDA or required to prove any health claims.

You did not say why you want to take this medication. It will not help in falling asleep. In general is helpful if you list your symptoms for one of us to provide an opinion based on medical information. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs.