With all due respect, I simply must agree with Curlyt66 and disagree with cteman. Here's why.
In the softcover version of Baby and Child Care by Benjamin Spock, M.D. (New York: Pocket Books, Giant Cardinal Imprint, 144th printing, January 1965), we find the following:
"If she [mother] becomes cross and tries to get his [her son's] movement out with an enema or a suppository . . . he may hold back anxiously (italicized) the next time . . . ." (Baby and Child Care 247.) Quite right.
"The very occasional enema or suppository the doctor may prescribe is not harmful in a child who has no training problem. But during a training struggle, when a child has been hanging onto his movement for dear life, if his mother in desperation resorts to an enema or suppository to get it out, he is apt to fight in rage and terror . . . ." (Id. 255-56.) Sadly, absolutely correct.
Dr. Spock also counselled against regular use of enemas or suppositories for constipation (or for toilet-training), describing it as "particularly important" that mothers not engage in such "unwholesome" treatments. (Id. 447.) Thank you, Dr. Spock.
As I wrote back on February 27, 2013, I hope the foregoing proves elucidative, responsive, and helpful. I loved Dr. Spock, and so I thought it appropriate to make fair use of his writings with a few apt quotations. Best wishes to all.