A study of the dynamic interfacial tension behavior of reacting acidic oil/alkaline solutions has been conducted for both an artificially acidified synthetic oil and a real crude oil for four different alkalis at various concentrations. The IFT values between a 10 mM acidified synthetic oil and various 25 mM alkaline solutions, before the minimum IFT value was reached, were found to be in the descending order : KOH, NaOH, Na2SiO3 and LiOH. The corresponding IFT values between diluted Lloydminster heavy crude oil and the same alkaline solutions, again before the minimum was reached, were found to be in the descending order : LiOH, NaOH, Na2SiO3 and KOH. The crude oil exhibited lower minimum IFT values against alkaline solutions than the synthetic acidified oil. The general trend of decreasing IFT towards a minimum value followed by an increase in IFT thereafter was noted for all solutions tested.