diff --git a/git-secrets b/git-secrets
index 3340cb1..1a0bb6b 100755
--- a/git-secrets
+++ b/git-secrets
@@ -11,7 +11,7 @@
 # on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 # express or implied. See the License for the specific language governing
 # permissions and limitations under the License.
-VERSION=1.4.1
+VERSION=1.5.0
 
 NONGIT_OK=1 OPTIONS_SPEC="\
 git secrets --scan [-r|--recursive] [--cached] [--no-index] [--untracked] [<files>...]
@@ -119,10 +119,13 @@ scan_history() {
 # Note: this function returns 1 on success, 0 on error.
 git_grep() {
   local options="$1"; shift
-  local files=("${@}") combined_patterns=$(load_combined_patterns)
+  local files=("${@}") patterns=$(load_patterns)
 
-  [ -z "${combined_patterns}" ] && return 1
-  GREP_OPTIONS= LC_ALL=C git grep -nwHEI ${options} "${combined_patterns}" -- "${files[@]}"
+  [ -z "${patterns}" ] && return 1
+  # Pass patterns one per line rather than as a single alternation: git's
+  # regex engine slows down sharply as one alternation grows.
+  printf '%s\n' "${patterns}" \
+    | GREP_OPTIONS= LC_ALL=C git grep -nwHEI ${options} -f - -- "${files[@]}"
 }
 
 # Performs a regular grep, taking into account patterns and recursion.