[R] warnings in glm (logistic regression)

[Taka Matzmoto]

Hello R users

I ran more than 100 logistic regression analyses. Some of the analyses gave 
me this kind warning below.

###########################################################
Warning messages:
1: algorithm did not converge in: glm.fit(x = X, y = Y, weights = weights, 
start = start, etastart = etastart,   ...
2: fitted probabilities numerically 0 or 1 occurred in: glm.fit(x = X, y = 
Y, weights = weights, start = start, etastart = etastart,   ...
###########################################################

For those cases for which I got the warning messages, shouldn't I rely on 
coefficents ? It looks like I can still extract coefficients from R outputs

Are there any ways to avoid these warning messages ? or are these due to the 
problems with my data (e.g., perfect separation)

Any help or advice would be appreciated

Thank you

TM