diff --git a/collector/global_variables.go b/collector/global_variables.go
index e1d52b9..2a9fa47 100644
--- a/collector/global_variables.go
+++ b/collector/global_variables.go
@@ -53,7 +53,7 @@ func (ScrapeGlobalVariables) Scrape(db *sql.DB, ch chan<- prometheus.Metric) err
 		if err := globalVariablesRows.Scan(&key, &val); err != nil {
 			return err
 		}
-		key = strings.ToLower(key)
+		key = validPrometheusName(key)
 		if floatVal, ok := parseStatus(val); ok {
 			ch <- prometheus.MustNewConstMetric(
 				newDesc(globalVariables, key, "Generic gauge metric from SHOW GLOBAL VARIABLES."),
@@ -113,3 +113,10 @@ func parseWsrepProviderOptions(opts string) float64 {
 
 	return val
 }
+
+func validPrometheusName(s string) string {
+	nameRe := regexp.MustCompile("([^a-zA-Z0-9_])")
+	s = nameRe.ReplaceAllString(s, "_")
+	s = strings.ToLower(s)
+	return s
+}