2407
This methodology was used to examine whether effects of caffeine ( a dose of 2 mg / kg ) could be explained in terms of reversal of the effects of caffeine withdrawal .
 Chemical: caffeine; Chemical: caffeine
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: caffeine; Chemical: caffeine