diff --git a/eth/gasprice/gasprice.go b/eth/gasprice/gasprice.go
index 8feb5ef24..00128a5dc 100644
--- a/eth/gasprice/gasprice.go
+++ b/eth/gasprice/gasprice.go
@@ -87,8 +87,7 @@ func NewOracle(backend OracleBackend, params Config) *Oracle {
 	if percent < 0 {
 		percent = 0
 		log.Warn("Sanitizing invalid gasprice oracle sample percentile", "provided", params.Percentile, "updated", percent)
-	}
-	if percent > 100 {
+	} else if percent > 100 {
 		percent = 100
 		log.Warn("Sanitizing invalid gasprice oracle sample percentile", "provided", params.Percentile, "updated", percent)
 	}
@@ -104,6 +103,16 @@ func NewOracle(backend OracleBackend, params Config) *Oracle {
 	} else if ignorePrice.Int64() > 0 {
 		log.Info("Gasprice oracle is ignoring threshold set", "threshold", ignorePrice)
 	}
+	maxHeaderHistory := params.MaxHeaderHistory
+	if maxHeaderHistory < 1 {
+		maxHeaderHistory = 1
+		log.Warn("Sanitizing invalid gasprice oracle max header history", "provided", params.MaxHeaderHistory, "updated", maxHeaderHistory)
+	}
+	maxBlockHistory := params.MaxBlockHistory
+	if maxBlockHistory < 1 {
+		maxBlockHistory = 1
+		log.Warn("Sanitizing invalid gasprice oracle max block history", "provided", params.MaxBlockHistory, "updated", maxBlockHistory)
+	}
 
 	cache, _ := lru.New(2048)
 	headEvent := make(chan core.ChainHeadEvent, 1)
@@ -125,8 +134,8 @@ func NewOracle(backend OracleBackend, params Config) *Oracle {
 		ignorePrice:      ignorePrice,
 		checkBlocks:      blocks,
 		percentile:       percent,
-		maxHeaderHistory: params.MaxHeaderHistory,
-		maxBlockHistory:  params.MaxBlockHistory,
+		maxHeaderHistory: maxHeaderHistory,
+		maxBlockHistory:  maxBlockHistory,
 		historyCache:     cache,
 	}
 }