Kellogg also opposed tea and coffee due to the caffeine content of those beverages. His view was that caffeine was a poison. Not only did he detail numerous physiological and developmental problems caused by caffeine, but he also suggested that caffeine usage could lead to moral deficiencies. He blamed the prevalence of these beverages not only on the prohibition of alcoholic beverages at the time, but also on the extensive marketing efforts organized by the producers of these products. Kellogg's view was that "nature has supplied us with pure water, with a great variety of fruit juices and wholesome and harmless flavors quite sufficient to meet all our needs."
