23121
This effect of naloxone was reversed by subcutaneous pretreatment with morphine .
 Chemical: naloxone; Chemical: morphine
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: naloxone, morphine 
Answer:
 Chemical: naloxone; Chemical: morphine