diff --git a/sexp.c b/sexp.c
index e86d8ebe..7f2bb666 100644
--- a/sexp.c
+++ b/sexp.c
@@ -1208,7 +1208,7 @@ sexp sexp_intern(sexp ctx, const char *str, sexp_sint_t len) {
     goto normal_intern;
   for ( ; i<len; i++, p++) {
     c = *p;
-    if ((unsigned char)c <= 32 || (unsigned char)c > 127 || c == '\\' || c == '.' || sexp_is_separator(c))
+    if ((unsigned char)c <= 32 || (unsigned char)c > 127 || c == '\\' || c == '.' || c =='#' || sexp_is_separator(c))
       goto normal_intern;
     he = huff_table[(unsigned char)c];
     newbits = he.len;
@@ -1940,7 +1940,7 @@ sexp sexp_write_one (sexp ctx, sexp obj, sexp out) {
                   sexp_tolower(str[3]) == 'n')))))
         ? '|' : EOF;
       for (i=sexp_lsymbol_length(obj)-1; i>=0; i--)
-        if (str[i] <= ' ' || str[i] == '\\' || sexp_is_separator(str[i]))
+        if (str[i] <= ' ' || str[i] == '\\' || str[i] == '#' || sexp_is_separator(str[i]))
           c = '|';
       if (c!=EOF) sexp_write_char(ctx, c, out);
       for (i=sexp_lsymbol_length(obj); i>0; str++, i--) {