The advent of voice assistants has radically transformed the retail industry, and conversational artificial intelligence has become a key factor in consumer behavior in voice commerce. This study conducts a comparative analysis of the effects of conversational artificial intelligence on spontaneous and intentional purchase decisions in voice commerce, using secondary data analysis. By examining existing data, we investigate the different effects of conversational artificial intelligence on impulsive and planned purchase decisions. Our findings indicate that conversational artificial intelligence has a significant impact on both spontaneous and intentional purchase decisions, although with significant differences in magnitude and context. It is clear that conversational artificial intelligence plays two distinct roles: on the one hand, it encourages impulsive purchases by offering personalized recommendations and attractive incentives that can persuade; on the other hand, it supports intentional buyers by providing the information and comparison tools necessary to make an informed decision. Our research contributes to the important discussion about voice commerce, offering retailers and marketers concrete strategies to improve the way they interact with customers and increase sales. The key is to make voice commerce strategies flexible and personalized based on the customer and their purchasing intent