I have been using flaxoil for over 10 years now (12 oz bottles). I have never heard (nor experienced)that it would go bad soon after opening. What you want to do is to make sure that it is always kept in the fridge. Flaxoil is one of the best thing you can add to your diet. When I first started using it ( 2 table spoons a day) I remember feeling a lot more energetic with that pleasant feeling that my legs were very light. Good luck with this fantastic product. I hope that this answers your question.