diff --git a/doc/src/fix_charge_regulation.rst b/doc/src/fix_charge_regulation.rst
index 091eeae417..fe77deb91e 100644
--- a/doc/src/fix_charge_regulation.rst
+++ b/doc/src/fix_charge_regulation.rst
@@ -13,8 +13,8 @@ Syntax
 
 * ID, group-ID are documented in fix command
 * charge/regulation = style name of this fix command
-* cation_type = atom type of free cations
-* anion_type = atom type of free anions
+* cation_type = atom type of free cations (integer or type label)
+* anion_type = atom type of free anions (integer or type label)
 
 * zero or more keyword/value pairs may be appended
 
@@ -27,8 +27,8 @@ Syntax
      *pIp* value = activity (effective concentration) of free cations (in the -log10 representation)
      *pIm* value = activity (effective concentration) of free anions (in the -log10 representation)
      *pKs* value = solvent self-dissociation constant (in the -log10 representation)
-     *acid_type* = atom type of acid groups
-     *base_type*  = atom type of base groups
+     *acid_type* = atom type of acid groups (integer or type label)
+     *base_type*  = atom type of base groups (integer or type label)
      *lunit_nm* value = unit length used by LAMMPS (# in the units of nanometers)
      *temp* value = temperature
      *tempfixid* value = fix ID of temperature thermostat
@@ -51,6 +51,9 @@ Examples
     fix chareg all charge/regulation 1 2 acid_type 3 base_type 4 pKa 5.0 pKb 6.0 pH 7.0 pIp 3.0 pIm 3.0 nevery 200 nmc 200 seed 123 tempfixid fT
     fix chareg all charge/regulation 1 2 pIp 3 pIm 3 onlysalt yes 2 -1 seed 123 tag yes temp 1.0
 
+    labelmap atom 1 H+ 2 OH-
+    fix chareg all charge/regulation H+ OH- pIp 3 pIm 3 onlysalt yes 2 -1 seed 123 tag yes temp 1.0
+
 Description
 """""""""""
 
diff --git a/src/MC/fix_charge_regulation.cpp b/src/MC/fix_charge_regulation.cpp
index 4358513095..cd035781c8 100644
--- a/src/MC/fix_charge_regulation.cpp
+++ b/src/MC/fix_charge_regulation.cpp
@@ -97,8 +97,8 @@ FixChargeRegulation::FixChargeRegulation(LAMMPS *lmp, int narg, char **arg) :
   energy_stored = 0;
 
   // necessary to specify the free ion types
-  cation_type = utils::inumeric(FLERR, arg[3], false, lmp);
-  anion_type = utils::inumeric(FLERR, arg[4], false, lmp);
+  cation_type = utils::expand_type_int(FLERR, arg[3], Atom::ATOM, lmp);
+  anion_type = utils::expand_type_int(FLERR, arg[4], Atom::ATOM, lmp);
 
   // set defaults and read optional arguments
   options(narg - 5, &arg[5]);
@@ -1398,11 +1398,11 @@ void FixChargeRegulation::options(int narg, char **arg) {
       iarg += 2;
     } else if (strcmp(arg[iarg], "acid_type") == 0) {
       if (iarg + 2 > narg) error->all(FLERR, "Illegal fix charge/regulation command");
-      acid_type = utils::inumeric(FLERR, arg[iarg + 1], false, lmp);
+      acid_type = utils::expand_type_int(FLERR, arg[iarg + 1], Atom::ATOM, lmp);
       iarg += 2;
     } else if (strcmp(arg[iarg], "base_type") == 0) {
       if (iarg + 2 > narg) error->all(FLERR, "Illegal fix charge/regulation command");
-      base_type = utils::inumeric(FLERR, arg[iarg + 1], false, lmp);
+      base_type = utils::expand_type_int(FLERR, arg[iarg + 1], Atom::ATOM, lmp);
       iarg += 2;
     } else if (strcmp(arg[iarg], "pH") == 0) {
       if (iarg + 2 > narg) error->all(FLERR, "Illegal fix charge/regulation command");