11231
When the treatment of these same rats was switched to 5 . 15 mu mol / kg / day of theophylline , the stepping recovery was only 51 +/- 12 % of that induced by caffeine .
 Chemical: theophylline; 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: theophylline; Chemical: caffeine