diff --git a/src/Metrics/Importer/PrometheusImporter.php b/src/Metrics/Importer/PrometheusImporter.php
index e3d7982..0062bd4 100644
--- a/src/Metrics/Importer/PrometheusImporter.php
+++ b/src/Metrics/Importer/PrometheusImporter.php
@@ -49,6 +49,10 @@ private function parseInfoLine(string $line, string $prefix)
 
     private function parseDataLine(string $line, string $prefix)
     {
+        if (strpos($line, ' ') === false) {
+            return;
+        }
+
         [$nick, $value] = explode(' ', $line);
 
         if ($prefix && strpos($nick, $prefix) === 0) {
diff --git a/tests/Metrics/ImporterTest.php b/tests/Metrics/ImporterTest.php
index 06c402a..c62f09f 100644
--- a/tests/Metrics/ImporterTest.php
+++ b/tests/Metrics/ImporterTest.php
@@ -15,6 +15,15 @@
 
 class ImporterTest extends TestCase
 {
+    public function testInvalidLine(): void
+    {
+        $registry = new Registry();
+        $info = new Info();
+        $importer = new PrometheusImporter($registry, $info);
+        $importer->fromString("");
+        $this->assertCount(0, $registry->toArray());
+    }
+
     public function testPrometheus(): void
     {
         $registry = new Registry();